SEOUL, South Korea (AP) -- Round-the-clock train and truck convoys are moving military hardware from the tense border with North Korea as the U.S. Army prepares to redeploy 3,600 troops to Iraq.

The massive logistical feat began July 7 and is moving hundreds of Abrams tanks, Bradley fighting vehicles, Humvees and artillery pieces to the southern port city of Busan to be shipped out under tight security.

About 3,600 troops from the Army's 2nd Infantry Division, dug into encampments between Seoul and the heavily fortified border with North Korea, will follow their equipment to Iraq.

The division's entire 2nd Brigade would begin pulling out of South Korea next week, and the entire unit would be in Iraq by the end of August, Gen. Richard Cody, the Army's vice chief of staff, said at the Pentagon on Friday. It is expected to operate in western Iraq with Marine units.

The redeployment -- one of the biggest realignments in a decade along the Cold War's last frontier -- was announced in May and signals the first significant change of U.S. troop levels in South Korea since the early 1990s.

The equipment is arriving round-the-clock at the Busan port, where soldiers are working two 12-hour shifts, Army spokeswoman Maj. Kathleen Johnson said.

The 2nd Infantry Division's 14,000 troops form the mainstay of the 37,000 U.S. troops in South Korea.

For decades, the U.S. troops have buttressed South Korea's 650,000-member military in guarding against the communist North's 1.1 million-member military, the world's fifth largest.

By Hans Greimel.