Thousands of American and South Korean troops conducted joint maneuvers Saturday, rankling North Korea (search), which denounced the exercises as a rehearsal for war.

U.S. officials said the weeklong exercise is one of several military drills the two allies conduct each year to boost their readiness against attack from North Korea.

This one involved some 17,000 U.S.-based troops and 6,000 soldiers stationed in South Korea (search). An unspecified number of South Korean troops also participated.

North Korea denounced the maneuvers as a rehearsal for a U.S.-led pre-emptive attack on the isolated communist state.

U.S. officials said the weeklong exercise is one of several military drills the two allies conduct each year to boost their readiness against provocations from North Korea.

Some 17,000 U.S.-based troops will join 6,000 soldiers stationed in South Korea who are part of the 32,500 American military force. An unspecified number of South Korean troops will also participate.

Secretary of State Condoleezza Rice (search) was in Seoul Saturday to consult with South Korean leaders on how to persuade North Korea to return to multinational negotiations aimed at ending its nuclear weapons programs.

North Korea says it is increasing its nuclear arsenal to defend itself from what it calls U.S. plans to invade and topple its communist regime. It says Rice's designation of North Korea as an "outpost of tyranny" confirms U.S. hostility toward the North.

Washington says it has no intention of invading, and has urged the impoverished country to give up its nuclear ambitions in return for better ties with the outside world.