A United Nations watchdog has warned that "racist hate speech" used by President Donald Trump and other US politicians has fuelled human rights violations.

A report by the Committee on the Elimination of Racial Discrimination (CERD), a UN-backed panel of independent experts, urged the US to respect international law and review its human rights policies.

It said the portrayal of migrants, refugees and asylum seekers "as criminals or ?as a burden by politicians and influential public figures at the highest level of the state party, particularly its president" may incite racial discrimination and hate crimes.

The White House dismissed the report, calling it "useless" and "biased".

"Their extreme bias continues to prove why no one takes them seriously," said White House spokeswoman Olivia Wales, who noted Trump's efforts to secure the US border.

"No-one cares what the biased United Nations' so-called 'experts' think, because Americans are living in a safer, stronger country than ever before."

The Geneva-based committee specifically highlighted Trump's immigration enforcement agenda in its report, saying it was "gravely concerned" about arbitrary identity checks that target refugees, asylum seekers, migrants and others who were perceived as such.

The report, released on Wednesday, did not mention specific incidents but did refer to Operation Metro Surge, the immigration crackdown in Minnesota. The surge sparked nationwide protests when two US citizens, Renee Good and Alex Pretti, were killed by federal agents.

Since those shootings, the Trump administration has scaled down its immigration enforcement in Minnesota.

The UN report said the two shootings amounted to "gross violations of international human rights law".

It also called on the US to halt immigration operations near schools, healthcare facilities and places of worship.

The panel also said it was "deeply concerned" by an increased use of racist hate speech, "including the use of derogatory and dehumanising language" that portrayed migrants, asylum seekers and refugees as criminals or as a burden.

It previously published reports condemning racism and discrimination in the US under multiple administrations, including former Presidents Barack Obama and Joe Biden.

Trump has embarked on sweeping efforts to deport undocumented migrants during his second term - a key election promise that drew mass support during the campaign.

He has sent thousands of federal agents into US cities, including Minneapolis earlier this year, to conduct sweeping raids as part of that deportation drive.

His comments on immigration have at times sparked a major backlash, such as in December when he said Somali immigrants should "go back to where they came from" and the US would "go the wrong way if we keep taking in garbage into our country".