WASHINGTON (AP) _ Haitians who flee their country by boat will not be allowed into the United States, but will either be taken to refugee camps in Panama or returned home, the Clinton administration said Tuesday.

In the latest shift in policy, the administration said it wanted to halt a surge of fleeing boat people. The announcement came a day after more than 3,000 Haitians were picked up by the U.S. Coast Guard.

And in a new show of military force, the administration ordered four more warships and 2,000 Marines to sail toward Haiti and prepare for a potential evacuation of U.S. citizens.

''Those who are not political refugees will be returned,'' said William Gray, President Clinton's special adviser on Haiti. ''Those who are refugees will be given safe haven - those that are picked up on the sea - in Panama.''

Gray said Haitians who apply at U.S. offices inside Haiti will be allowed to come to the United States if they are granted refugee status based on a well-founded fear of persecution.

In an earlier change of a policy that he had adopted from the previous administration, Clinton announced on May 8 that Haitians with a well-founded fear of persecution would be allowed to come to the United States to pursue their asylum claims or go to a third country.

But a surge in refugees turned into a tidal wave Monday, with the U.S. Coast Guard intercepting 3,247 Haitians in 70 boats, doubling the previous single-day high set in May 1992. More than 100 Haitians died when a boat capsized. Nearly 700 had been picked up by midday Tuesday and hundreds more were expected, a Coast Guard spokesman said.

The flow has swelled as the Clinton administration has tightened economic sanctions against Haiti in an effort to force out the military leaders who ousted President Jean-Bertrand Aristide in September 1991.

Michael Barnes, a former congressman and close adviser to exiled Haitian President Jean-Bertrand Aristide, said he was confident Aristide would oppose the new U.S. policy.

''For the people of Haiti who are trying to escape from the reign of terror, this is a step backwards,'' Barnes said.

Amnesty International USA called the new policy a double standard contrary to the intent of the 1980 Refugee Act to treat all refugees equally.

''It appears that the Clinton administration and the U.S. Congress are still afraid of Haitian refugees,'' said William Schulz, the organization's executive director.

The latest shift, coupled with flip-flops on U.S. policy toward Bosnia, China and Somalia, raised again questions about Clinton's consistency on foreign policy as he headed for Europe to meet with leaders there and attend an economic summit.

''The president clearly has a major foreign policy challenge,'' said Rep. Lee Hamilton, D-Ind., chairman of the House Foreign Affairs Committee. ''I don't think this change on Haitian refugee policy is going to impact that overall image all that much. But the broader question (of policy shifts) is something he clearly has to contend with.''

Gray said the first safe haven site would be in Panama and that agreement in principle also had been reached with the Caribbean nations of Dominica and Antigua. He said the agreement with Panama was for six months.

In Barbados, Antigua Prime Minister Lester Bird said Tuesday his country will allow the United States to process 2,000 Haitians during six months. The United Nations High Commissioner for Refugees will operate the center, he said.

Later, Clinton called Bird, President Guillermo Endara of Panama, and Prime Minister Eugenia Charles of Dominica to thank them for providing safen havens on their soil. Clinton also invited Ernesto Perez Balladares, the president- elect of Panama, to meet with him at the White House on July 20. Balladares accepted the invitation, the White House said.

Gray noted that any ''safe haven'' will be temporary, and that the Haitians will be repatriated when the crisis in their country is over.

Asked about the possibility of an invasion of Haiti, Gray said, ''There is no military invasion imminent.'' He defined imminent as the next several days.

Nevertheless, he said that a military option ''is on the table,'' and that the administration is ''looking at that situation as it deteriorates.'' He said the sudden deployment of the warships was necessary because the deteriorating situation ''poses a threat to the safety of Americans.''

Gray made the announcement after President Clinton discussed Haiti on Tuesday morning with his top foreign policy advisers, including Defense Secretary William Perry and Gen. John Shalikashvili, chairman of the Joint Chiefs of Staff. Perry visited Panama last month.

Pentagon spokesman Dennis Boxx said the new deployment will bring the number of U.S. warships in the region to about a dozen and would enable the military force ''to deal with any contingency.''

The 2,000 Marines on board the four ships are specially trained to conduct emergency evacuations under hostile conditions.

The sailors and warships headed for Haiti had just returned to the United States on June 24, having just completed a six-month deployment in the Mediterranean Sea, the Adriatic Sea off Yugoslavia, and in the waters off Somalia.

Gray argued that the new safe haven policy was a continuation of Clinton's announcement on May 8 that Haitian boat people would no longer be forcibly repatriated to Haiti.

The new policy came less than three weeks after the hospital ship USNS Comfort, anchored near Kingston, Jamaica, began to carry out the asylum interviews called for under Clinton's May 8 plan.

The new task force of warships is expected to arrive off Haiti later this week, a senior defense official said, speaking on condition of anonymity.

The additional ships being dispatched from Norfolk, Va., are led by the USS Inchon, a helicopter assault ship. The others include the USS Trenton, the USS Portland and USS Spartanburg County.

They will join a larger amphibious assault ship, the USS Wasp, which has been in the region conducting training exercises with 650 Marines on board.