North Korea warned yesterday that "dark clouds of nuclear war" are gathering over the peninsula and vowed to strengthen its atomic arsenal as it marked the anniversary of the 1950-1953 conflict.

Rodong Sinmun, newspaper of the ruling communist party, accused the US and its ally South Korea of trying to provoke another war with their pledge of a US nuclear "umbrella" over the South.

"A touch-and-go situation has been created on the Korean peninsula... with dark clouds of a nuclear war gathering as the hours tick by," it said in a lengthy commentary marking the anniversary, carried by the official news agency.

The paper said a new war could break out any time and the North would continue to strengthen its nuclear arsenal.

"As long as the US hostile policy continues, we will never give up our nuclear deterrent and even strengthen it," Mr Rodong said.