The United States has moved more warships and aircraft near the Korean Peninsula, expanding its military presence in the region as South Korea prepares to host North Korean athletes in Winter Olympics next month.

The USS Wasp, an upgraded US Marine Corps amphibious assault ship that can carry troops and a crop of fighter jets including the F-35, arrived in southern Japan on Sunday.

The US Pacific Air Forces announced last week that it had deployed three B-2 “Spirit” stealth bombers along with some 200 personnel from Whiteman Air Force Base in Missouri to the Pacific island of Guam.

Earlier, the US Navy’s USS Carl Vinson aircraft carrier departed for the western Pacific on what the Pentagon said was a routine mission. The strike group is expected to arrive in the region before the Olympics begin on February 9.

North Korea, which has been engaged in a long-running standoff with the US over its nuclear and ballistic missile programs, blasted the move as an attempt to derail recent talks between the two Koreas.

“Such moves are an unpardonable military provocation chilling the atmosphere for improved inter-Korean relations,” the North’s ruling party said in a commentary.

Seoul and Pyongyang held their first formal talks in over two years last Tuesday after Pyongyang said expressed willingness to send a delegation to the February 9-25 games in Pyeongchang.

The two neighbors held a new round of talks on Monday, trying to hammer out the details of Pyongyang’s plans for the upcoming sports event.

Following Monday’s discussions, the South Korean Unification Ministry said in a mobile text message that the North had requested working talks to be held on January 17.

Washington has welcomed the talks, unnamed officials within Donald Trump’s administration said, noting that the increasing US military presence off North Korean territories only represented routine training and scheduled upgrades.

After failing to stop the North’s frequent test-launches of ballistic missiles, Washington has stepped up military drills off the Korean Peninsula. American military forces have even simulated capturing North Korea’s nuclear weapons in one of the war games, which involved troops from Japan and South Korea as well.