U.S. Weighs Boost in Forces in S. Korea to Counter Any Invasion by the North : Asia: Options range from sending more support troops to deploying dozens of additional bombers and ships.

WASHINGTON â€”  The Clinton Administration must decide soon on how rapidly to strengthen U.S. armed forces in South Korea to deter or, if necessary, repel an invasion by North Korea.

President Clinton and his senior national security advisers are considering a package prepared by Defense Secretary William J. Perry that outlines options ranging from a modest increase in support troops to deployment of dozens of additional bombers and warships.

The pressure for new military moves has been mounting. Although Congress has generally supported Clinton’s response to North Korea’s refusal to allow inspections of its nuclear facilities, some key Democrats and Republicans have begun to complain publicly that Clinton is not doing enough to prepare for possible war.

But officials said any decision would probably be delayed as the Administration tries to untangle the confusion resulting from apparently erroneous statements on U.S. intentions made by former President Jimmy Carter at the end of his visit to North Korea.

Carter, traveling as a private citizen, told North Korean President Kim Il Sung that the Clinton Administration was suspending its drive for U.N. sanctions while it assessed a new compromise proposed Thursday by North Korea.

Clinton, however, had already vowed to keep pressing for economic sanctions in response to North Korea’s defiance of international safeguards against nuclear weapons proliferation.

Clinton warned reporters Friday not to “overreact� to Carter’s statement. “I gave my position yesterday and it hasn’t changed,� the President told reporters on a trip to Chicago.

A senior Administration official acknowledged Friday that the Administration is worried that Carter’s assertion to Kim could give other countries at the United Nations an excuse to drag their feet in considering the sanctions proposal, easing pressure on North Korea.

“That’s one reason why we moved . . . so quickly yesterday with a statement to say we are proceeding with consultations on sanctions at the U.N.,� the official said.

Key Administration officials said they would hold up any further action on the North Korean offer until after today, when Carter leaves the North Korean capital of Pyongyang and can talk with them on a secure telephone line to provide more details of his conversations with Kim.

Even then, Robert L. Gallucci, the Administration’s point man on Korean issues, said no major decisions are likely until early next week, “assuming that we have good conversations, clear conversations with President Carter tomorrow or Sunday.�

Pentagon officials said the military package presented to Clinton included these options:

* Sending more military support personnel to South Korea to make it easier for the services to deploy more combat and logistic troops to reinforce troops now in place, should North Korea invade the South.

* Deploying up to 40 more warplanes to the region, including F-117 radar-evading Stealth bombers in South Korea and B-52 long-range bombers on Guam. The Navy would send an extra aircraft carrier to the area. And the Army and Marines would beef up their forces.

* Making preparations for rapid deployment of substantial numbers of ground troops to the area as reinforcements, if war should break out. Gen. Gary E. Luck, U.S. commander in South Korea, has said he would need 400,000 more troops, besides the 37,000 Americans in position now, if North Korea were to invade.

The Pentagon has also been taking steps to modernize existing forces and bolster supplies of spare parts and ammunition to facilitate the arrival of reinforcements.

Perry and Gen. John M. Shalikashvili, chairman of the Joint Chiefs of Staff, have sent Patriot air-defense missiles to South Korea, along with artillery-locating radar and dozens of Apache helicopters, intended to replace aging Cobra gunships that U.S. forces had been using.

Even so, except for the addition of the Patriots, the bulk of the U.S. effort has been modest and barely visible. And some steps that Perry had said earlier he would take--such as bolstering allied ammunition supplies--have still not been carried out.

Senior Administration officials have argued that they have kept the effort low-key for two reasons: They want to avoid provoking the North Koreans, who have warned that the mere imposition of sanctions might set off a war. And they want to mollify South Korea, which fears that a real mobilization would panic the country and hurt the economy.

Despite North Korea’s strident rhetoric, U.S. intelligence officers have reported that they have seen no unusual movements of troops or equipment in North Korea that might suggest that the country is gearing up for an invasion. “Everything looks normal,� one official said.

But the Administration has been under mounting pressure from conservatives to beef up U.S. forces in South Korea, particularly in the face of North Korea’s increasing threats of war as the United States began to press for U.N. sanctions.

In a sign of congressional unease over the U.S.-North Korean confrontation, the Senate voted, 93 to 3, Thursday to urge Clinton to bolster U.S. forces in South Korea to a level where they could “deter and if necessary repel an attack� from North Korea.

What is propelling the Administration most, however, is timing. U.S. commanders in the field figure that it would take at least several months to prepare allied forces there for reinforcements and ultimately to deploy extra troops and equipment--and the clock is ticking fast.

Administration officials spent much of Friday trying to distance themselves from Carter. “President Carter carried no message from us, no message from the President . . . neither concessions nor threats,� Gallucci, a State Department official, said.

Times staff writers David Lauter in Chicago, Michael Ross and Stanley Meisler in Washington and Sam Jameson in Tokyo contributed to this report.