WASHINGTON — South Korean and North Korean soldiers exchanged gunfire across the Demilitarized Zone (search) Thursday morning, the South Korean military said.

North Korea fired first with four shots at a South Korean army position near the town of Yonchon at 6:10 a.m. The South fired 17 rounds in response one minute later, said Maj. Lee of the South Korean Joint Chiefs of Staff.

The South reported no injuries among its soldiers, and it was not immediately known if any casualties were suffered on the North's side. Over the decades, violence has periodically broken out at the DMZ, though such engagements have tapered off in recent years and are now considered rare.

The clash between the two neighbors comes amid heightened tensions on the peninsula over the closed-off communist country's nuclear ambitions.

Diplomacy had appeared to be making headway Wednesday, when the United States was told by Chinese officials Pyongyang (search) was no longer insisting on bilateral negotiations on its nuclear weapons programs, Fox News learned.[...]