North Korea has threatened to sever military ties with South Korea, accusing Seoul of allowing US troops to flaunt their presence in two border areas used for inter-Korean exchanges and tourism.
In an unusual statement carried by Pyongyang's official KCNA news agency late Tuesday, the North's military said South Korea's "servile" attitude to the United States was putting inter-Korean military relations in jeorpardy.
Military accords signed by the Koreas to control overland exchanges across the heavily fortified border were close to "dead," it said.
In 2002, the two Koreas, still on truce since the end of the 1950-53 Korean War, created joint administration areas (JAAs) through which they have built two cross-border roads.
Under a 1953 armistice, the United Nations Command led by US troops has direct control over the southern part of the 250-kilometer (155-mile) inter-Korean buffer zone.
An unnamed North Korean military spokesman, however, insisted in Tuesday's statement that South Korea had refused to stop US soldiers from "strutting about" in the areas managed by the two Koreas.
He also accused the United States of seeking to "interfere in and hamstring" inter-Korean co-operation and exchanges.
US soldiers have came close to the border line in the JAAs without prior notice, "watching vehicles moving, photographing areas of the north side and jesting its guard personnel on duty by finger and body languages," he said.
"This has created disturbing developments which may escalate confrontation and tension in the above-said areas," he said.
South Korean police went "little short of reducing the agreements calling for a military guarantee already concluded between the north and the south to dead ones," the spokesman said.
"This servile attitude compels the north side to ponder over whether it can sit with the South Korean military to handle such important issues as halting the military confrontation on the Korean Peninsula in the future."
Economic exchanges between the two Cold War rivals have greatly increased following an inter-Korean summit in 2000 that led to the opening of cross-border roads.
But North Korea has balked at holding high-level military talks with South Korea on easing tension.