WASHINGTON -- After weeks of bellicose rhetoric that appeared to endorse an expansion of the war in Yugoslavia, Britain is now inclined to oppose a U.S.-proposed military blockade to thwart oil tankers supplying the Serbian army, Pentagon officials say.

British diplomats insisted yesterday that no final decision had been made on the armed interdiction of oil and other supplies arriving at Yugoslav ports. But with Germany and France opposing a blockade, the waning British resolve appears to have doomed the U.S. initiative.

"Looks like we're on our own," one U.S. Navy officer said yesterday.

For the United States and its allies, an oil blockade raises the prospect of a hostile encounter with a Russian ship on its way to Yugoslavia to deliver oil.

Last weekend, a Russian oil tanker pulled into a port in the Yugoslav republic of Montenegro for the first time since January 1998, carrying 15,000 tons of refined oil, Navy sources said.

In March, 415,000 barrels of oil were unloaded in the Yugoslav ports of Kotor Bay and Bar. Last month, that rose by 15,000 barrels.

"It gets to the point: Do you want to start a war with Russia? That seems to me to be a legitimate issue," said Nathaniel Kern, president of Foreign Reports, an oil-industry newsletter, summing up the Europeans' reluctance.

"If you end up having to back down because a Russian warship has accompanied a Russian oil tanker, that isn't going to be good one way or the other," Kern said.

U.S. helicopter crashes

The wrangling over terms of the blockade occurred yesterday as allied forces in the Balkans suffered their first casualties.

Two U.S. Army pilots died in a fiery crash of their Apache attack helicopter during a training mission. It was the second crash since the helicopters were deployed in Albania two weeks ago.

President Clinton has not ordered the Apaches into action, but Lt. Col. Garrie Dornan, a spokesman for U.S. Task Force Hawk, which includes the Apaches, said the crashes would not affect training or the eventual deployment of the helicopters.

News of the servicemen's deaths greeted Clinton as he arrived in Germany to meet with U.S. forces, including the three captured soldiers released last weekend by Yugoslavia.

"I know this is hard," Clinton told pilots and ground crews at Spangdahlem Air Base in Germany. "I know too many of these pilots are flying long hours with too little rest. I know the stress and anxiety must be unbearable."

As diplomatic efforts continued, Clinton and NATO officials cautioned that the air war over Yugoslavia will likely go on for months. U.S. Army Gen. Wesley K. Clark, NATO's supreme commander, appeared to warn refugees that they might be spending next winter displaced from their homes, if not from Kosovo itself.

"We have to look very much ahead, past the summer, into the autumn, the winter and even the next spring," Clark said.

The NATO allies are struggling not only with the shape of a peace agreement but also with the fundamental matter of how they will wage war on Yugoslavia. With the allies divided over whether to back a naval blockade, allied warships might be restricted to voluntary "visits" of cargo ships bound for Yugoslav ports.

Ground force reassessed

NATO officials also acknowledged that they are having to reassess the size of the ground force they eventually would send into Kosovo to police a peace accord.

Clark told the president yesterday that securing peace would take more troops than the original 28,000 -- including 4,000 Americans -- that were planned before airstrikes and Serbian purges devastated the province, said Mike Hammer, a spokesman for the National Security Council.

NATO denied a news report that top military strategists had agreed to a force of 60,000 combat troops who could enter Kosovo by July, if Serb forces have begun retreating. Jamie P. Shea, NATO's spokesman, acknowledged that the original figure was being adjusted, almost certainly upward.

If anything, military officials said, the 60,000-troop figure is far too low, even after months of bombarding the 40,000 Serb troops deployed there and even if they have begun retreating.

One NATO military officer said officials would not draft detailed troop plans until ordered to do so by the North Atlantic Council, NATO's political arm.

For weeks, NATO diplomats have hinted that ground troops could be sent into a "semi-permissive" environment, where weakened Serb forces could not put up much resistance.

But U.S. officials still insist that combat troops would enter only with permission and a peace accord in hand, or with an overwhelming assault force.

U.S. Army and NATO officers estimate that any force would likely be composed of at least one-third American troops, owing to the U.S. power in both logistics and intelligence capabilities.

"What I told the president in no uncertain terms is that it's either permissive or nonpermissive," said Gen. Henry H. Shelton, chairman of the Joint Chiefs of Staff. "And if it's nonpermissive, we'll assume we could face hostile action and we'll prepare our forces accordingly."

As the air war proceeded, a relief convoy from the Greek branch of Doctors of the World apparently came under attack yesterday, though no injuries were reported.

Mary Catherine De Riedmatten, an official with the group, said a food-and-medicine convoy of three trucks and two cars was making its way toward Kosovo's provincial capital, Pristina, when a bomb exploded close enough to rock the lead car.

Convoy passengers said they heard a plane after the explosion but could not see it. De Riedmatten said the cars in the convoy were marked with the group's logo, and the trucks were painted with white and blue stripes at the instruction of NATO.

It was the fourth Doctors of the World convoy into Kosovo. As they had done previously, group members had notified NATO of their route through the Greek Ministry of Defense. The convoy had expected to travel from Macedonia Tuesday night but was delayed until yesterday.

NATO Maj. Gen. Walter Jertz denied that NATO had launched an attack. And U.S. Maj. Gen. Charles Wald said there were no allied military actions in the area at the time. Nevertheless, the Greek government asked NATO to investigate the incident.

The U.S. military identified the two Army Apache aviators as Chief Warrant Officer 3 David A. Gibbs, 38, of Ohio, and Chief Warrant Officer 2 Kevin L. Reichert, 28, of Wisconsin. Their hometowns were not disclosed.

The helicopters crashed in a mountainous region of northeast Albania, near the Yugoslav and Macedonian border. The pilots were training for the conditions they would face in combat, Wald said.

Pub Date: 5/06/99