Using welding torches, South Korean navy commandos forced their way into a captured North Korean submarine Thursday but were slowed in their search of the main deck by concerns it was booby-trapped.
South Korean officials have said the sub's crew was likely either dead or had escaped after their craft became entangled in a fishing net Monday.Still, they took no chances and had guns and tear gas at the ready when they entered the protruding tower that contains the periscope.
"We checked the sub's upper access deck but found no signs of humans there," said Lt. Col. Kim Jong-sook, a spokesman for the Joint Chiefs of Staff.
Kim said that further work to open a secondary hatch leading to the sub's main deck was temporarily halted on the advice of a former North Korean navy commando, who warned it could be booby-trapped.
In the area that was searched, navy officials found two South Korean-made plastic beverage containers - what they said was a strong indication that the vessel was returning after dropping or picking up spies.
The sub sank Tuesday while being towed to Donghae naval base.
The search Thursday began shortly after the submarine was raised. Navy divers racing an approaching storm attached four car-size yellow air bags to lift the submarine 110 feet to the surface where an awaiting tug boat then towed it to shore.
The small, 70-ton Yugo-class submarine normally carries a crew of about six and is the sort used primarily to transport spies and conduct coastline surveillance.
The sub was found in the general area where a larger North Korean sub ran aground in 1996. That incursion triggered a 53-day manhunt that left 24 North Korean infiltrators and 13 South Koreans dead and relations between the two Koreas at their worst in years.
In Seoul, President Kim Dae-jung reaffirmed that the latest incident won't affect his policy of engagement toward the communist North, and hoped to open the reclusive nation through more cooperation and contacts.
Opposition politicians and some newspaper editorials have criticized Kim for not taking a harder line with North Korea because of the sub episode.