North Korea accused the United States of pushing a crisis over its suspected nuclear weapons programs into a ‘‘tight corner’’ and claimed Washington was preparing an invasion of the Communist country.While vowing to counter any military attacks, Pyongyang also said today it wants to avoid war and reiterated its demand for direct talks with Washington. The comments came amid intensifying condemnation by Pyongyang of massive joint US-South Korean military exercises now taking place. Washington bills the annual manoeuvres as defensive. Nevertheless, the US has mustered an impressive show of force for the games, including the aircraft carrier USS Carl Vinson and six US F-117 Nighthawk stealth fighters, here for the first time in a decade.North Korea blames the war games for heightening tensions in the region. Despite the standoff, Washington promised to immediately send 40,000 tons of food to impoverished North Korea as part of its commitment of 100,000 tons of food, a UN envoy said today in Beijing. The announcement by Maurice Strong, a Canadian aide to UN Secretary General Kofi Annan, came after warnings by aid agencies that donations have dropped sharply, jeopardising programs that feed millions of North Koreans.North Korea’s official Rodong Sinmun said today that US military moves against the nation were in full swing.