North Korea on Sunday claimed that South Korean military had opened gunfire on North Korea's outpost in the demilitarized zone (DMZ) between the two countries, dpa reported.
The North's official Korean Central News Agency claimed that the shots were a "planned provocation." South Korea denied any knowledge of the incident.
"The gunfire from the South was a serious threat to the safety of our police guards who were carrying out their normal border duty ... (the gunfire) triggered an explosive situation on the border," the Korean Central News Agency said.
"The gunfire is a planned provocation designed to create tension within the DMZ. We urge the South to take every responsible action to ensure that such an incident will not be repeated."
But South Korea's military denied that the event had taken place.
"We've checked out with our command control unit, and found that no such such gunfire took place," a South Korean military officer was quoted as saying by South Korean news agency Yonhap.
The North's claim came while South Korea's Navy began salvage operations for one of its vessels which sank near the North Korean maritime border on March 26 after an explosion which has not yet been clarified.
Rescue operations for 45 missing sailors of the 1,200-ton Cheonan warship were halted late Saturday. The body of one crewman was recovered from the stern of the vessel.
The Cheonan patrol ship sank in 45 metres of water near the disputed maritime border with North Korea after the unexplained explosion. Fifty-eight crewmen were rescued. Most of the 45 missing sailors were believed to be trapped in the stern of the ship, which broke apart.
While the cause of the explosion remains under investigation, Seoul has not completely ruled out North Koran involvement in the sinking. On Friday, Defence Minister Kim Tae Young said a torpedo could have been a possible cause for the blast.
He had said earlier that North Korean sea mines, remnants of the 1950-53 Korean War, were another possibility.
However, Seoul has been careful to avoid attaching direct blame to Pyongyang.
The area where the sinking occurred was the site of naval clashes between North and South Korea in 1999, 2002 and 2009.