Military officers from North Korean and the American-led U.N. Command met Friday to discuss the deadly sinking of a South Korean warship blamed on Pyongyang — a rare and likely tense encounter.

A team of international investigators concluded in May that a North Korean submarine fired a torpedo that sank the warship in March. But North Korea denies any involvement and has threatened war if punished. The issue has raised tensions on the Korean peninsula and complicated efforts to bring the North back to the negotiating table on its nuclear program.

In their second meeting in recent days, colonel-level officers from the North and the U.N. Command, which oversees the truce that ended the Korean War, held talks at the border village of Panmunjom inside the Demilitarized Zone dividing the Koreas, command spokesman Kim Yong-kyu said. The command was expected to release a statement on the talks later in the day.

Their first meeting produced no progress as North Korea renewed its calls to conduct its own investigation into the sinking of the 1,200-ton Cheonan. The U.N. Command has conducted its own investigation.

The command said in a statement on Thursday that the two sides would discuss details of the date, agenda and protocols for higher-level talks among their generals on the sinking.

The meeting came as South Korea and the U.S. prepare to hold joint military exercises despite oppositions from North Korea and its key ally China.

The military drills are to run Sunday through Wednesday with about 8,000 U.S. and South Korean troops, about 20 ships and submarines and 200 aircraft, including the USS George Washington aircraft carrier, and the U.S. Air Force's F-22 stealth fighter.

North Korea often accuses the U.S. and South Korea of staging military drills as a rehearsal for an attack on North Korea. Washington and Seoul say the exercises are purely defensive and they have no intention of invading the North.

The U.S. stations 28,500 soldiers in South Korea, a legacy of the Korean War. Fighting ended with a truce, not a peace treaty, leaving the peninsula still technically at war.