The security chief of impeached South Korean President Yoon Suk-yeol, under investigation for blocking Yoon's arrest, has resigned and says any further efforts to detain the ex-leader must avoid bloodshed.
Yoon's short-lived declaration of martial law on December 3 has plunged one of Asia's most vibrant democracies into a period of unprecedented political turbulence.
As a top court deliberates over MPs' decision to impeach Yoon, who is holed up at his hillside residence, anti-graft officers have also opened a criminal investigation for possible insurrection.
Those officers were last week stopped from bringing Yoon in for questioning in a six-hour stand-off with the Presidential Security Service (PPS), headed by Park Chong-jun.
Investigators have a warrant for Yoon's arrest and have said they are determined to detain him for questioning.
Park, a former senior police official, was questioned by police on Friday over his role in last week's stand-off and his office announced he had submitted his resignation.
As he arrived at the police headquarters in downtown Seoul, he told reporters the attempt to arrest a sitting president was wrong and "there should not be any physical clash or bloodshed under any circumstances".
Acting President Choi Sang-mok, just two weeks in office and thrust into a political cauldron, on Friday called for a fresh way to resolve the stalemate between investigators and Yoon's security.
He proposed parliament prepare a bill to appoint a special prosecutor.
Earlier, Choi had vetoed an opposition-backed special prosecutor bill to probe the martial law declaration, saying it had no guarantee an independent person would be appointed to lead the probe.
Last Friday, hundreds of PSS agents blockaded the presidential compound and thwarted investigators from trying to arrest Yoon.
The investigators were pulled back because of the risk of a clash.
Officials of the Corruption Investigation Office for High-ranking Officials (CIO), which is leading the investigation, have said PSS agents were carrying firearms during the stand-off, although no weapons were drawn.
The investigators obtained a new arrest warrant this week.
Lawyers for Yoon have said the arrest warrant was illegal and invalid.
Yoon is under a separate Constitutional Court trial reviewing parliament's impeachment of him on December 14 to decide whether to remove him from office permanently or reinstate him.
His lawyers have said Yoon will accept that verdict.
As Yoon awaits his fate, polls released this week showed a revival of support for his ruling People Power Party (PPP) and calls for his permanent removal slipping.
A Gallup Korea survey published on Friday showed 64 per cent of respondents back Yoon's removal from office, compared to 75 per cent who favoured it soon after the martial law declaration.
The PPP's approval rating rose to 34 per cent, a level similar to the period before Dec. 3, in the poll this week, from 24 per cent about a month ago.
Analysts said the prolonged uncertainty over Yoon's fate has not only emboldened his supporters but softened some critics concerned that the liberal opposition Democratic Party leader, who is himself on trial on allegations of criminal wrongdoings, may become president.
