S. Korea, U.S. troops raise alert level

SEOUL, May 28 (UPI) -- U.S. and South Korean troops are on high alert, and surveillance and reconnaissance picked up to answer what officials termed a grave threat from North Korea.

The South Korean Defense Ministry said allied troops, including, 28,000 U.S. soldiers stationed in South Korea, raised their Watch Condition to the second-highest level from Watchcon 3 to Watchcon 2, The New York Times reported Thursday.

Tensions on the Korean peninsula have been roiling since North Korea conducted its second nuclear test Monday, followed by the test-firing of short-range missiles.

The higher alert level allows for increased use of reconnaissance planes and spy satellites, and a more aggressive collection and analysis of electronic signals from the North, South Korean defense officials said.

The North's state-controlled media warned Thursday "even a minor accidental clash could lead to nuclear war."

North Korea stepped up its threats against South Korea and the United States Wednesday, warning of a "powerful military strike" if North Korean ships were stopped or searched as part of a U.S.-led operation to intercept vessels believed to be carrying unconventional weapons, the Times said.

South Korea agreed to join the operation, known as the Proliferation Security Initiative, after North Korea's nuclear test despite Pyongyang's warning not to do so.

In its Wednesday statement, North Korea also said it "no longer felt bound" to honor the 1953 armistice reached to end the Korean conflict.