President Bush is expected Monday to formally announce a plan to redeploy about 70,000 American troops currently stationed in Europe and Asia. U.S. lawmakers are addressing potential concerns of allies who may fear losing the protection of the American military presence.

The plan President Bush is expected to outline would mark the largest restructuring of U.S. forces globally since World War II. Besides relocating 70,000 American soldiers, the changes would also affect an additional 100,000 military support staff and family members.

The Pentagon is reported to have been working on the realignment plan for more than a year. It is aimed at giving U.S. military commanders more flexibility in sending forces to trouble spots in the Middle East and Central Asia.

The majority of American troops would be relocated from bases in European countries, such as Britain and Germany. The changes also would affect South Korea, where South Korean students and workers have called for the withdrawal of U.S. troops from the country.

U.S. and South Korean officials last month agreed to move 8,000 American soldiers from Seoul to the city of Pyongtaek, 80 kilometers to the south. The two countries also are discussing Washington's plan to withdraw about a third of the 37,000 American troops in the country.

Speaking on the U.S. television program, Fox News Sunday, Senate Foreign Relations Committee Chairman Richard Lugar expressed concern that decreasing the U.S. military presence in South Korea could have a negative impact on six-nation talks on ending North Korea's nuclear programs.

"I think this is a situation for very careful, continuing negotiations with our South Korean friends, and I would think, with the six-power talks, we ought not to do anything that is going to jeopardize the success, potentially, of those talks," said Senator Lugar.

The chairman of the Senate Armed Services Committee, John Warner, told CNN's Late Edition, Washington's decision to move troops is not an indication of U.S indifference.

"In Korea, you've seen the South Korean military strengthen itself each year, to where it now can be less dependent on the U.S. forces," he explained. "But we haven't lessened our commitment, in either the South Korean peninsula or in Europe, and our allies know that, because we have been in consultation with them."

The highest-ranking Democrat on the Senate Armed Services Committee, Carl Levin, said the changes were necessary to better address the threat of international terrorism. He also appeared on CNN.

"This has been in the works for a long time, and there are some things that we should do to redeploy troops, so they are in the best position possible for what the new threats are," he said.

There are more than 100,000 American troops in Europe, and another 100,000 in the Asia-Pacific region. About 150,000 U.S. soldiers are now in Iraq and Afghanistan.