After a dramatic six-hour long standoff with security, South Korean police have called off an attempt to arrest suspended President Yoon Suk Yeol.

The 150 officers involved found themselves helplessly outnumbered - first by the large number of pro-Yoon supporters who had gathered outside his residence before sunrise, and then by a human wall of security staff inside the property.

Police were trying to carry out an arrest warrant issued earlier this week after Yoon ignored three summonses for him to appear for questioning.

The politician is currently under investigation for abusing his power and inciting an insurrection when he tried to impose martial law in early December.

Dozens of police vans lined the street outside Yoon's residence in central Seoul early on Friday morning, before the arrest team - made up of police officers and members of the Corruption Investigation Office (CIO) - began moving towards the building at about 08:00 local time (23:00 GMT).

The operation started out with a 20-strong team, but quickly multiplied to some 150 people. Even then, they were outnumbered.

While about half of the team was able to get inside, they were locked for hours in a standoff with presidential security officers - who are still responsible for protecting Yoon, despite him being stripped of his powers - and a military unit responsible for protecting the city of Seoul.

At one point Yoon's security team engaged in a "confrontation" with the investigating officers, an official with Seoul's Joint Chiefs of Staff told news agency AFP.

"We've determined that the arrest is practically impossible," said the CIO, which has been investigating Yoon's short-lived martial law declaration last month.

If they had been successful, Yoon would have become the first sitting president to be arrested in South Korea's history.

Yoon's "refusal of the legal process" is "deeply regrettable", the CIO said, adding that next steps will be decided after a review.

Yoon's supporters, who have been camped out in front of the presidential residence for days, cheered in song and dance as the suspension was announced. "We won!" they chanted. Some carried "Stop the Steal" signs - an echo of the call used by US President Donald Trump's supporters after he lost the 2020 election.

The CIO said that concern for the safety of the team on the ground was a factor in their decision to call off the attempted arrest.

The presidential security service has said they will hold the CIO and police accountable for trespassing, adding that the team had injured some of their staff members.

This development is not unexpected, given Yoon's defiance throughout the investigation process.

Experts say that as a former chief prosecutor, Yoon is well aware of the legal loopholes available for his defence.

Investigators have until 6 January to arrest him before the current warrant expires.

This means they may attempt to arrest Yoon again over the weekend, although this could be logistically challenging as the crowds are likely to swell.

They can also apply for a new warrant and try to detain him again.

Before the attempt was stood down, Yoon's security team told the news agency they had been "in negotiation" with the investigators who sought to access the president.

Police have opened a criminal case against the chief of Yoon's security service and his deputy, and summoned them for questioning, according to Yonhap.

Yoon's legal team was also seen entering the residence slightly past noon local time.

His lawyer Yoon Gab-keun earlier said they would take legal action over the arrest warrant, arguing that investigators lacked the authority to detain him.

Meanwhile, Park Chan-dae, the floor leader of the main opposition Democratic Party, has criticised Yoon for not upholding his promise to take legal and political responsibility for his botched martial law attempt.

"[It was] a complete lie," Park said, urging the CIO to attempt to arrest Yoon again today.

The CIO, which has only been operating for four years, was created in response to public anger over former president Park Geun-hye and her excesses. She was impeached by parliament in December 2016, and removed from office three months after.

The extent of the CIO's jurisdiction, however, has been challenged by other agencies - and its failure to deal with Yoon could be seen as an embarrassing loss.

South Korea has been in political chaos since the martial law attempt on 3 December, with wide rifts opening in parliament between Yoon loyalists and those seeking to unseat him.

Days and nights of protest culminated in the opposition-dominated parliament voting to impeach Yoon on 14 December, their second attempt to do so after the majority of his ruling party members boycotted the first vote.

Two weeks later, parliament voted to impeach his replacement, acting president Han Duck-soo - the first time an acting president had been impeached since South Korea became a democracy.

Han was supposed to lead the country out of its political turmoil, but opposition MPs argued that he was refusing demands to complete Yoon's impeachment process.

On Friday, prosecutors also indicted on insurrection charges army chief Park An-su, who was named martial law commander during the brief declaration, and special forces commander Kwak Jong-geun, according to Seoul-based news outlet Yonhap.

They are to face trial while in prison.

Additional reporting by Jake Kwon in Seoul