North Korea warns US of 'disastrous consequences' after military exercise

North Korea said Tuesday that its military would be put on high alert and is ready to launch an attack, ramping up tensions after weeks of rhetoric directed against the United States and South Korea, whom it accuses of instigating hostility.

A spokesman for the North's military warned the U.S. of "disastrous consequences" for moving a group of ships, including an aircraft carrier, into a South Korean port.

Reclusive North Korea has often threatened to attack the South and sometimes even the U.S., but its threats have rarely materialized into action. Its hostile rhetoric is widely seen as a means to assert its domestic and international political agenda.

"In this connection, the units of all services and army corps level of the KPA (Korean People’s Army) received an emergency order from its supreme command to re-examine the operation plans already ratified by it and keep themselves fully ready to promptly launch operations any time," the military spokesman said.

"The U.S. will be wholly accountable for the unexpected horrible disaster to be met by its imperialist aggression forces' nuclear strike means," the spokesman said in the statement carried by KCNA, the official North Korean news agency.

In March, the North declared it was no longer bound by the armistice that was signed with the U.S. and China and ended fighting in the 1950-53 Korean War. Pyongyang then threatened to use nuclear weapons to attack U.S. and South Korean territories if provoked.

The North has defied international warnings not to build nuclear and long-range missiles and is believed to have enough fissile material to build up to 10 nuclear bombs, but most intelligence analysts say it has yet to master the technology to deploy such weapons.

The U.S., which has 28,500 troops stationed in the South and regularly engages in drills with its ally, said the aircraft carrier USS George Washington was merely leading a group of ships to visit South Korea in a routine port call.

South Korea's Defense Ministry said on Monday the ships were taking part in a routine maritime search and rescue exercise. The ministry characterized any criticism by North Korea as "wrong."

Secretary of Defense Chuck Hagel, on a visit to the Demilitarized Zone between the two Koreas last week, vowed to maintain the U.S. military presence in the area.

The impoverished North's large but aging conventional military is considered unfit to fight an extended modern battle, but that does not mean it is unwilling to strike.

In 2010, the North staged surprise attacks against the South that killed 50 people, an act of aggression unprecedented since the war.

An attempt at dialogue in August led to the re-opening of a jointly run factory park that had been shut amid rising tension in April, but talks have since hit a stalemate.

Concurrently, reunifications of family members divided by the war were set to resume in August after a three-year hiatus, but in September the North’s Committee for Peaceful Reunification of Korea abruptly called off the meetings, citing joint military exercises carried out by South Korea and the U.S.

The Committee said reunifications could not resume “until there can be a normal atmosphere where dialogue and negotiations can be held.”

Al Jazeera and Reuters