SEOUL, Korea, Republic Of - After a prolonged standoff, South Korean police on Thursday detained a labour union official for his alleged involvement in organizing anti-government protests that turned violent last month.

In a massive show of force, more than 2,000 uniformed police officers surrounded a Buddhist temple where Korean Confederation of Trade Unions President Han Sang-gyun had been holed up for nearly a month.

The swarm of police, which cut off streets around the stately Jogyesa Temple in downtown Seoul, has become a common sight as thousands have gathered in recent months to protest what they see as worsening labour conditions and an attack on personal and political freedoms by conservative President Park Geun-hye.

Led by a senior monk, Han walked out of the temple flanked by dozens of labour union members and temple followers who created a path for him by linking their hands. The temple has long provided refuge for political dissidents trying to avoid arrest.

"Let's destroy the attempts to worsen labour laws," an emotional Han shouted, shortly before he stepped outside the temple's main gate and was handcuffed by police officers who took him away. He called for a general strike starting Wednesday. Another large general demonstration against the president is planned for Dec. 19.

Anti-government forces are protesting the president's proposal to rewrite labour laws so companies would have more freedom to fire workers and replace them with temporary employees, although policymakers say such changes would be critical for improving a bleak job market for young people. Critics also raise concerns over what they see as Park's unwillingness to tolerate dissent.

Park's government has cracked down on press freedoms and been criticized for incompetence in the aftermath of a ferry sinking that killed more than 300. There is widespread resistance to the government's decision to require middle and high schools to use only state-issued history textbooks starting in 2017, which critics see as an attempt to whitewash the dictatorships that preceded South Korea's bloody transition toward democracy in the 1980s.

Police plan to soon request a formal arrest warrant for Han who could face charges including obstruction of justice and illegal assembly for his alleged involvement in nine different anti-government protests this year, including a massive demonstration in November that left dozens of people injured.

Police may also push for a rarely used sedition charge against Han for his involvement in a Nov. 14 protest that turned violent, said an official from the Seoul Metropolitan Police Agency, who didn't want to be named, citing office rules.

The KCTU labour union defined Han's detainment as labour repression. KCTU spokesman Park Sung-shik could not immediately confirm how many workers would participate in the Dec. 16 general strike.