The Bush administration responded sternly Monday to an annihilation threat from North Korea, saying while it had no intention of attacking, it was determined to protect the United States if North Korea launched a long-range missile.

"Should North Korea take the provocative action of launching a missile the U.S. would respond appropriately, including by taking the necessary measures to protect ourselves," Julie Reside, a State Department spokeswoman, said.

Still, the United States has no intention of invading or attacking North Korea, Reside said. Rather, she said, the United States and other countries that have negotiated with North Korea are seeking a fundamentally different relationship. She said it must be based on the complete and verifiable elimination of North Korea's nuclear weapons and nuclear program.

"We and our partners in the six-party process continue strongly to urge North Korea not to launch a long-range missile and, instead, to return to the six-party talks," she said in a statement.

The six-party talks, suspended by North Korea, involved negotiations by the United States, China, South Korea, Japan and Russia with Pyongyang.

South Korea's former negotiator, Song Min-soon, is due in Washington later in the week for talks, and North Korea's nuclear and missile programs are certain to be on the agenda, said a U.S. official, who spoke on condition of anonymity because the official is not authorized to announce visit. Song is now South Korea's national security adviser.

North Korea vowed on Monday to respond with an "annihilating" nuclear strike if its atomic facilities were attacked pre-emptively by the United States.

The warning was a stepping up of the North's customary anti-U.S. vitriol, in which it often accuses Washington of plotting an attack. The reclusive North has recently come under heightened scrutiny after reports by the United States and Japan that it has taken steps to prepare for a test of a long-range missile.

White House spokesman Tony Snow refused to respond to what he called "a hypothetical situation."

"It is a statement about what may happen if something that hasn't happened, happened — if you follow my drift," he said.

The North's Korean Central News Agency, citing an unidentified "analyst" with the state-run Rodong Sinmun newspaper, accused the United States of harassing Pyongyang with war exercises, a massive arms buildup and increased aerial espionage by basing new spy planes in South Korea.