Military officers from North Korea and the United Nations Command in South Korea are to hold another round of meetings.
Colonels from the two sides will meet in the Demilitarized Zone between North and South Korea Tuesday morning.
This will be the fourth in a recent series of discussions meant to pave the way for a meeting between generals of the United Nations Command in South Korea, which the U.S. leads, and the North Korean military. The generals at that meeting are expected to discuss the sinking of a South Korean navy ship in the Yellow Sea.
The South Korean and U.S. governments, among others, blame a North Korean torpedo for sinking the Cheonan on March 26. Pyongyang denies responsibility.
A new concern for South Korea is the fate of the seven-man crew of a squid fishing boat. North Korea seized the boat Sunday off the east coast.
A spokesman for South Korea's Unification ministry, Chun Hae-sung, says there has been no communication from the North, so far, about the fishermen.
Chun says Seoul requested Pyongyang on Sunday to swiftly release the men in accordance with international law and practice.
South Korea's coast guard says the North questioned the four South Koreans and three Chinese aboard for allegedly violating Pyongyang's exclusive economic zone.
South Korean officials say the boat and crew were taken to the North Korean port of Songjin.
North Korea last year detained four South Korean fishermen for illegally entering its waters. They were released after one month.
The new incident follows North Korea's threats of retaliation for South Korea naval war games over the past few weeks.
The latest exercise, which ends Monday, involves anti-submarine training. South Korean officials say it is meant to send a message to North Korea not to engage in further provocations.
The two Koreas have lived with an uneasy truce since their devastating three-year war against each other in the early 1950's. There have been minor flare-ups over the decades, including clashes at sea, the killings of soldiers in the Demilitarized Zone and North Korean attacks on South Korean targets.