The New Nation - Internet Edition

AFP, Seoul

South Korean troops are on guard against any military provocation by North Korea after the communist state ordered a border clampdown amid worsening ties, the defence ministry said Wednesday.

The North on Monday imposed strict border controls and ordered the expulsion of hundreds of South Koreans working at the Kaesong joint industrial estate, in protest at what it calls the Seoul government's confrontational policy. It also halted a cross-border cargo rail service and a popular day tour.

"In response to the North's December 1 measure, surveillance and control operations are being stepped up against (any) naval attacks and attempts to kidnap fishing boats," the ministry said.

Special training programmes are also being implemented to cope with "contingencies" along the heavily fortified land border, it said in a report to parliament.

Some analysts believe the North may provoke a limited clash around the disputed border in the Yellow Sea, the scene of bloody naval battles in 1999 and 2002.

The ministry report also said the North in 2007 deployed new ballistic missiles with a range of 2,500-4,000 km (1,562-2,500 miles). It was building up ground forces including tanks, artillery and special warfare troops.

A defence ministry spokesman declined to elaborate on the missiles.