North Korea accused South Korean troops of firing a shell yesterday across the inter-Korean border.
Pyongyang's official Korean Central News Agency (KCNA), citing military sources, said South Korean troops fired at a North Korean post in the eastern sector of the inter-Korean border early Saturday.
"The shell dropped just near a post of the Korean People's Army [KPA], posing a grave threat to the lives of KPA servicemen on routine guard duty," it said.
A South Korean defense ministry spokesman said authorities were investigating the allegation.
KCNA also accused South Korean warships of regularly intruding into disputed waters claimed by both Koreas off the western coast.
"Those reckless military provocations cannot be construed otherwise than as their deliberate and premeditated moves to strain the situation," it said.
"The South Korean military authorities should not run amok, pondering over serious consequences to be entailed by such military provocations," it said.
Ever since the Korean War ended in a volatile armistice there have been sporadic exchanges of gunfire across the tense border.
But tensions along the last Cold War frontier have eased greatly since a historic inter-Korean summit in 2000.
Since then, inter-Korean ties have not deteriorated seriously despite a renewed stand-off over North Korea's nuclear weapons drive and the lack of official dialogue between the two sides.