Should we bother with this weekends meet?

North Korea has accused the United States of using military drills in South Korea as a launch pad for a nuclear war and has scrapped the armistice with Washington that ended hostilities in the 1950-53 Korean War.

North Korea, which has one major ally, neighbouring China, threatens the United States and its "puppet", South Korea, on an almost daily basis.

"Since the United States is about to ignite a nuclear war, we will be exercising our right to preemptive nuclear attack against the headquarters of the aggressor in order to protect our supreme interest," the North's foreign ministry spokesman said in a statement carried by the official KCNA news agency.

North Korea conducted a third nuclear test on February 12, in defiance of U.N. resolutions, and declared it had achieved progress in securing a functioning atomic arsenal. It is widely believed the North does not have the capacity to deliver a nuclear strike on the mainland United States.

The North's unnamed foreign ministry spokesman also said it would be entitled to take military action as of March 11 when U.S.-South Korea military drills move into a full-scale phase as it had declared the truce invalid.

It is the latest in an escalation of tough words from both sides of the armed Korean border this week as the U.N. Security Council deliberates a resolution to tighten financial sanctions and a naval blockade against the North.

North Korea, which held a mass military rally in Pyongyang on Thursday in support of its recent threats, has protested against the U.N. censures of its rocket launches. It says they are part of a peaceful space programme and that the criticism is an exercise of double standards by the United States.

But North Korea's shrill rhetoric rarely goes beyond just that. Its latest armed aggression against the South in 2010 came unannounced, bombing a South Korean island killing two civilians. It is widely accused of sinking a South Korean navy ship earlier in the year, killing 46 sailors.

North Korea was conducting a series of military drills and getting ready for state-wide war practice of an unusual scale, South Korea's defence ministry said earlier on Thursday.

South Korea and the United States, which are conducting annual military drills until the end of April, are watching the North's activities for signs they turn from an exercise to an actual attack, a South Korean official said.

"It hasn't been frequent that the North conducted military exercise at the state level," South Korea's defence ministry spokesman, Kim Min-seok, said. "The North is currently conducting various drills on land, at sea and aerially.

"We are watching the North's activities and stepping up readiness under the assumption that these drills can lead to provocation at any time."

Kim declined to confirm news reports that the North has imposed no-fly zones off its coasts in a possible move to fire missiles, but he said any flight ban limited to near the coast would not be for weapons with meaningful ranges.

A top North Korean general said on Tuesday said Pyongyang was scrapping the armistice. But the two sides remain technically at war as the civil war did not end with a treaty.

South Korea's military said in a rare warning on Wednesday that it would strike back at the North and target its leadership if Pyongyang launched an attack.

(Editing by Nick Macfie)