Police have arrested the leader of an umbrella union group on charges of holding unauthorized mass rallies amid the COVID-19 pandemic. 

Yang Kyung-soo, chief of the Korean Confederation of Trade Unions (KCTU), was arrested at a KCTU office in central Seoul, early on Thursday. 

The arrest comes 20 days after a local court issued an arrest warrant for him. About two weeks ago, the police sought to arrest him but failed as KCTU members blocked officers from entering the building. 

Yang is accused of organizing massive rallies in central Seoul between May and July in violation of laws on demonstrations and infectious disease control.

The KCTU plans to hold a rally at 11 a.m. Thursday in front of Jongno Police station, where Yang has been detained.