South Korean police has surrounded a temple in downtown Seoul since Tuesday attempting to search union members who were believed to take refuge there amid the country's large-scale railway strike.

Some 100 police have been deployed to the Jogyesa temple, the center of South Korea's Zen Buddhism, as the railway workers' strike entered its 17th day when the country is celebrating its Christmas holiday.

Local police said three union members of the state-run Korea Railroad Corp. (KORAIL) and one deputy labor union leader who evaded arrest during a police raid on Sunday have been hiding in the temple since Monday night.

Around 600 police on Sunday forced their way into the headquarters of the Korean Confederation of Trade Unions (KCTU), one of the two largest umbrella labor organizations, where the strike leaders were believed to be hiding and finally took more than 120 protesters to nearby police stations.

The police had searched the union building from top to bottom for nine hours but failed to find out the union leaders after a Seoul court issued arrest warrants for six of them who rejected summons to appear for questioning.

Denouncing the forced entry, the KCTU vowed to launch a general strike on Saturday.

South Korean President Park Geun-hye on Monday said the government will not made "unprincipled" compromise over the railway workers' strike.

The government urged the striking unionists to immediately return to work, saying it can no longer tolerate the "illegal strike." Despite the government's insistence that the new KORAIL' s bullet train service would not be privatized, local union and protesters firmly kept its stance on canceling the project.

This longest strike in South Korean history has affected high- speed KTX, ITX, subway and cargo train operations. The KTX and freight service operations are currently down to 70 percent and 30 percent, respectively, according to KORAIL.

The number of subway trains has been reduced by 7 percent during morning rush hour and 11 percent during the evening in Seoul and surrounding Gyeonggi Province.

Some 8,700 out of a total of 27,000 employees of KORAIL had been joining in the strike and 1,070 of them returned to their workplaces as of Sunday.