Bush's announcement quickly drew scathing criticism on Monday from former NATO commander Wesley Clark and former ambassador Richard Holbrooke, two senior advisers to Democratic presidential candidate John Kerry.
Clark said the 10-year plan, unveiled by Republican Bush in a campaign speech to US veterans in Ohio, would "significantly undermine US national security".
"As we face a global war on terror with al-Qaida active in more than 60 countries, now is not the time to pull back our forces, and I question why President Bush would want to do this now," Clark said in a statement.
"This ill-conceived move and its timing seem politically motivated rather than designed to strengthen our national security," said the retired general who commanded NATO and US forces in Europe from 1997 to 2000.
He said removing US forces from the Korean peninsula could "send a dangerous signal of weak US resolve" to North Korea's Kim Jong-Il at a crucial moment in efforts to persuade him to scrap his nuclear weapons programmes.
Clark (R) says the new plan will
only burden military families
Holbrooke added: "How can we withdraw troops from Korea while engaged in a delicate negotiation with the North Koreans? There's a country that really does have weapons of mass destruction."
A pullout from Europe, he said, would further strain relations with NATO allies, "be interpreted as the distancing of the US from NATO, and will set back US efforts to encourage greater NATO participation in Iraq".
Clark disputed Bush's argument that US troops could be deployed to hotspots much faster from the continental US, and said the plan would do nothing to ease the burden on overstretched American forces.
"Worse, it will increase the burden on many military families as troops will be separated from their families during more frequent and unaccompanied deployments to Eastern Europe," he said.
"How can we withdraw troops from Korea while engaged in a delicate negotiation with the North Koreans? There's a country that really does have weapons of mass destruction"
adviser to John Kerry
Holbrooke, a former ambassador to Germany as well as assistant secretary of state for Asia, said Bush's plan was "pretty alarming".
"There is no question in my mind that this will weaken our national security," said Holbrooke, who has been tipped as a potential secretary of state if Kerry wins the White House in the November election.
"This is another example of the administration's unilateralism ... It is not going to save us money. It will cost billions of dollars to bring these troops home," he said in an interview with CNN.
Holbrooke said both the Germans and South Koreans would be very unhappy with Bush's announcement that a total of 60,000 to 70,000 US troops would be repatriated.
Bush has criticised Kerry for his
pledge to pull out troops from Iraq
The criticisms came as Bush pressed his attacks on Kerry's security stance, slamming the Democrat's pledge to bring back a sizeable number of troops from Iraq within six months of taking office.
"I think that sends the wrong signal," Bush said, adding that it could encourage Iraqi insurgents to hold on, discourage US troops from completing their mission and leave allies wondering whether the US meant what it said.
Bush also ridiculed Kerry's protest vote against a bill authorising $87 billion for postwar operations in Afghanistan and Iraq. "There's nothing complicated about supporting our troops in combat," the president said.