Reclusive North Korea is to cut its last communication channel with the South because war could break out at “any moment”, it said yesterday, days of after warning the United States and South Korea of nuclear attack.

The move is the latest in a series of bellicose threats from North Korea in response to UN sanctions imposed after its third nuclear test in February and to “hostile” military drills joining the United States and South Korea.

The North has already stopped responding to calls on the hotline to the US military that supervises the heavily armed Demilitarised Zone (DMZ) and the Red Cross line that has been used by governments of both sides.

“Under the situation where a war may break out at any moment, there is no need to keep north-south military communications, which were laid between the militaries of both sides,” the North’s KCNA news agency quoted a military spokesman as saying.

“There do not exist any dialogue channel and communications means between the DPRK and the US and between the north and the south.”

The Pentagon condemned the latest escalation in North Korean rhetoric, with spokesman George Little calling Pyongyang’s declaration “yet another provocative and unconstructive step.”

The US military said on March 15 it was bolstering missile defences in response to threats from the North, including to conduct a pre-emptive nuclear strike against the US.

Despite the shrill rhetoric, few believe North Korea, formally known as the Democratic People’s Republic of Korea (DPRK), will risk starting a full-out war.

North and South Korea are still technically at war anyway after their 1950-53 civil conflict ended with an armistice, not a treaty, which the North says it has since torn to pieces.

The “dialogue channel” is used on a daily basis to process South Koreans who work in the Kaesong industrial project, where 123 South Korean firms employ more than 50,000 North Koreans to make household goods.

About 120 South Koreans are stationed at Kaesong at any one time on average.

It is the last remaining joint project in operation between the two Koreas after South Korea cut off most aid and trade in response to Pyongyang’s shooting of a South Korean tourist and the sinking of a South Korean naval vessel blamed on the North.

The North’s military spokesman for its “supreme command” did not mention Kaesong, which has suffered temporary shutdowns before.

The South’s government said it would take steps to ensure the safety of the workers at Kaesong. It did not elaborate.