On the second day of his new US presidency, Donald Trump cracked down further on immigration - using an executive order that "suspends the physical entry of aliens engaged in an invasion of the United States through the southern border".

His press secretary confirmed that 1,500 additional troops would be sent to toughen the border with Mexico. Thousands more could reportedly be sent in time.

Trump also gave his first interview of his second term, telling Fox News he could reform or disband the Federal Emergency Management Agency (FEMA) over its response to last year's Hurricane Helene.

Speaking to Sean Hannity, he also defended his use of presidential pardons for hundreds of his supporters who were convicted over a riot at the US Capitol in 2021.

Trump was inaugurated as president again earlier this week, and swiftly set about enacting some of his key campaign promises - largely using executive orders.

These carry the weight of law, but can be overturned by subsequent presidents or the courts. Several of those planned by Trump face legal challenges.

Here is a summary of some of Trump's actions so far.

'Repel, repatriate and remove'

After his initial flurry of executive orders, Trump issued another demanding that the government "suspends the physical entry of aliens engaged in an invasion of the United States through the southern border". It calls for officials to "immediately repel, repatriate and remove" those individuals.

'National emergency'

Trump has proclaimed that "America's sovereignty is under attack", declaring this to be a national emergency that allows him to free up more funding to reinforce the border with Mexico.

The same directive tells officials to relaunch efforts to build a border wall with Mexico that was started under his first presidency. This is not an executive order and it is unclear how such an effort might be funded.

Closing the border

The president has told the military to "seal the borders" - citing the flow of illicit drugs, human smuggling and crime relating to crossings.

Birthright citizenship

Trump has ordered that officials deny the right to citizenship to the children of migrants either in the US illegally or on temporary visas.

But the 14th Amendment to the US Constitution has long been interpreted to enshrine that right, and Trump's order was immediately challenged in federal court.

Terrorism designation for gangs and cartels

Trump has designated drug cartels and international gangs as foreign terrorist organisations - adding the likes of Salvadoran gang MS-13 to a list that includes the so-called Islamic State.

'Remain in Mexico' and no more 'catch and release'

Trump has re-implemented his "Remain in Mexico" policy from his first term. This returned about 70,000 non-Mexican asylum seekers across the border to await hearings, before being cancelled by President Joe Biden.

The same order demands the end of "catch and release", a policy that allows migrants to live in US communities while they await their hearings. Trump has previously promised "the largest deportation program in American history", but this could face legal and logistical challenges.

The order also shut down a major Biden-era immigration pipeline: a sponsorship initiative that allowed up to 30,000 migrants from Cuba, Haiti, Nicaragua and Venezuela to fly to the US. It had been designed to cut illegal crossings.

Death penalty for some immigrant criminals

Trump has ordered that the federal death penalty be reinstated. Executions have not happened in recent years. It would apply to any "capital crime committed by an alien illegally present in this country" and anyone convicted of murdering a law-enforcement officer.

Refugee resettlement

Trump has suspended the US refugee resettlement programme, although details remain unclear.

Pull out of the Paris agreement (again)

Trump has signed off on withdrawing from the Paris climate agreement - the landmark international deal to limit rising global temperatures. He will have to wait a year before it happens. He previously withdrew in 2017, before Biden re-entered.

'Energy emergency'

Trump has declared a "national energy emergency", promising to fill up oil reserves. In his inaugural address, he vowed to "drill, baby, drill" for more fossil fuels.

Alaskan fuel

He signed an executive order titled "unleashing Alaska's extraordinary resource potential", pledging to "unlock" oil, gas and other natural resources from the state.

End Green New Deal

Trump has halted the Green New Deal, a series of Biden measures that were aimed at boosting green jobs, regulating the fossil fuel industry and limiting pollution.

He has ordered agencies to halt funds appropriated through two laws, the Inflation Reduction Act and another law on infrastructure and jobs. He said the US would end leasing to wind farms and revoke what he calls an electric vehicle "mandate".

Trump signed an executive order to begin the process of withdrawing the US from the UN's health body, the World Health Organization (WHO).

This marks the second time Trump has ordered the US be pulled out of the WHO, after Biden re-entered it. He was critical of how the Geneva-based institution handled Covid-19.

Transgender people

Trump has declared that the US will only recognise "two sexes, male and female. These sexes are not changeable and are grounded in fundamental and incontrovertible reality". It is expected to affect transgender policies relating to government communications, civil rights protections and federal funding, as well as prisons. It will affect official documents like passports and visas.

In the same executive order, Trump ended all government programmes, policies, statements and communications that promote or support "gender ideology".

DEI

On Tuesday evening a memo, followed by another executive order, shut down all the offices of diversity, equity and inclusion (DEI) programmes within the federal government "with immediate effect" but giving them until 1700 ET on Wednesday to comply.

The day before, after being inaugurated, Trump had halted all such programmes labelling them "radical and wasteful". The administration has also promised further actions that may affect the private sector.

Trump has signed a directive postponing by 75 days the implementation of a law that would ban Chinese-owned app TikTok in the US. The platform had briefly been shut the day before the inauguration, to comply with the law - which demands that a new American owner be found.

Trump formerly backed a TikTok ban, but indicated he reversed course after his campaign videos attracted billions of views. Asked what the action does after he signed it, he said it gives him the right to "sell it or close it".

Pardoning hundreds who stormed US Capitol

Trump announced he was issuing pardons for nearly 1,600 of his supporters who were arrested in the riot at the US Capitol in 2021.

Trump has repeatedly referred to those arrested in the riot as "hostages". At least 600 were charged with assaulting or impeding federal officers.

Commuting sentences of Oath Keepers, Proud Boys

Trump also commuted sentences for members of the Oath Keepers and Proud Boys, far-right groups who were convicted of seditious conspiracy in relation to the riot.

A lawyer for former Proud Boys leader Henry "Enrique" Tarrio, who was jailed for 22 years for seditious conspiracy, said his client also expected to be released.

A full pardon

Trump said he signed a full and unconditional pardon for Ross Ulbricht, the creator of Silk Road, a dark web marketplace where illegal drugs were sold. Ulbricht was convicted in 2015 in New York in a narcotics and money-laundering conspiracy and sentenced to life in prison, but Trump joined libertarians in claiming the conviction was an example of government overreach.

Doge and Elon Musk

Trump has signed a directive creating the Department of Government Efficiency (Doge) - a new advisory body on cutting government costs. It is expected to be led by Elon Musk - who Trump separately said would get an office for about 20 employees.

Freeze on federal hiring

Another order halts any new federal hiring - except within the US military and several other categories - until the Trump administration has full control over the government.

Federal employees returning to the office

Trump has also signed a memorandum mandating that federal workers must work in the office and are not allowed to work from home.

Censorship

Another directive orders the "restoration of freedom of speech and preventing government censorship". It directs the attorney general to investigate the activities of officials at certain agencies - such as the Department of Justice, Securities and Exchange Commission, and Federal Trade Commission - during the Biden era.

Political prosecutions

Another executive order seeks to end the "weaponisation of government against political adversaries". It mandates a review of the work of various law enforcement and intelligence agencies under Biden to "identify any instances" of alleged weaponisation, and then recommend "appropriate remedial actions".

'American-First'

Trump has announced he is pausing foreign aid, outlining that he wants a review of foreign assistance programs. Karoline Leavitt, the White House press secretary, said this was part of a new "American-First" foreign policy.

Israeli settler sanctions

Trump rescinded sanctions that Biden began imposing on extremist Israeli settlers and settler groups in the occupied West Bank nearly one year ago. The last administration's executive order had targeted Israelis who were "Undermining Peace, Security, and Stability in the West Bank", in response to a surge in attacks on Palestinians and their property in the territory.

Cuba

Trump wants to undo Biden's recent decision to remove Cuba from the US list of state sponsors of terrorism. He could also reinstate sanctions against Venezuela. Both countries were frequent targets of his ire during his first administration.

Regulatory freeze

Another order directs federal agencies to refrain from issuing any new regulations until the Trump administration has full control of the government.

Unvaccinated federal workers

As part of a directive reversing Biden-era policies, Trump revoked a mandate that federal workers must be vaccinated with the Covid vaccine. He has promised to reinstate the 8,000 military service members who were discharged due to the Pentagon's Covid vaccine mandate - with full backpay.

Tackling inflation

Trump has signed a directive asking every US federal department and agency to address the cost of living. The directive, which is not an executive order, asks agencies to look at lowering the costs of housing, healthcare and key household items, groceries and fuel.

It asks for a report in 30 days. It not clear how the Trump administration intends to lower these costs - and this is not detailed in the directive.

'Gulf of America' and Alaska's Mount Denali

Trump has directed the secretary of the interior to change the name of the Gulf of Mexico to the "Gulf of America".

The same order also directs the secretary to rename Alaska's Mount Denali to Mount McKinley - in honour of America's 25th president whose tariff policies Trump admires. President Barack Obama changed the name from McKinley to Denali to reflect what North America's highest peak was called by native tribes.

Tariffs

After bracing for weeks for a trade war with the US, Canada has - for now - evaded import taxes that Donald Trump had threatened to impose on the country as soon as he takes office.

But Trump said on Monday the tariffs on Canada and Mexico could come on 1 February, and ordered federal officials to review US trade relationships for unfair practices, including those with Canada, Mexico and China.

• Canada avoids Trump's tariffs - for now

Secret documents

At a rally before his inauguration, Trump said he would release classified documents related to the assassination of President John F Kennedy in 1963, a subject of countless conspiracy theories, as well as the 1968 killings of Senator Robert Kennedy and civil rights leader Martin Luther King Jr. In his Fox interview in the days after his inauguration, he said these files would be released "immediately" when he received them.

Crypto pile

Trump has championed cryptocurrency, and his election saw the value of Bitcoin increase by 30%. Some believe Trump will move quickly to create a federal "Bitcoin stockpile" - a strategic reserve similar to the US's stockpile of gold and oil - that he has said would serve as a "permanent national asset to benefit all Americans".