Accident in Bosnia Kills 3 U.S. Envoys : Balkans: Vehicle carrying diplomats plunges from mountain. Fatalities include Washington’s point man in effort to resolve conflict. Clinton vows to press ahead.

Three senior U.S. officials, including the American diplomat most intimately involved in negotiating an end to the war in Bosnia-Herzegovina, were killed in an accident Saturday as they traveled to the Bosnian capital, Sarajevo, with a new peace plan.

The armored vehicle carrying U.S. envoy Robert Frasure and nine other people careened off the treacherous Mt. Igman road leading to Sarajevo when an embankment apparently gave way. It plunged down a ravine, exploded and burst into flames, U.N. and U.S. officials said.

Frasure, 53, was a deputy assistant secretary of state and the U.S. representative to the five-nation Contact Group mediating the Bosnian war. Killed with him were Joseph Kruzel, 50, deputy assistant secretary of defense for European affairs and NATO policy, and Air Force Col. Samuel Nelson Drew, 47, a National Security Council aide.

Frasure and Drew were killed immediately, and Kruzel died shortly after of injuries he suffered in the crash, U.S. officials in Washington said.

The three men were part of a high-level U.S. delegation that had been shuttling a new peace proposal among the political leaders of the former Yugoslav federation. Their deaths will sidetrack the delicate negotiations at least temporarily. The loss especially of Frasure, Washington’s point man in the Balkans for most of the year, is a serious blow to diplomatic efforts to reach a peaceful settlement to a devastating war that has claimed more than 200,000 lives.

President Clinton, who described the wreck as a “tragic accident,” said the negotiations started by Frasure and the other members of the delegation will continue.

“I would think that the thing that they would want us most [to do] is to press ahead, and that is what we intend to do,” Clinton said in Jackson Hole, Wyo., where he is vacationing.

A French U.N. peacekeeper was also killed, and three Americans and two French peacekeepers were injured, U.N. officials in Sarajevo said.

U.S. Assistant Secretary of State Richard Holbrooke, who headed the mission, and Lt. Gen. Wesley Clark, of the Joint Chiefs of Staff, were traveling in a different vehicle and were not hurt. They went on to Sarajevo, where Bosnian government officials went to the U.S. Embassy to offer their condolences.

“Three brave, brilliant, fine American career government officials, who were devoting their lives to the cause of peace in this part of the world, have died in this accident,” Holbrooke told the gathering of officials and reporters. “We lost three-fifths of our negotiating team today.”

Holbrooke said he and the rest of the delegation would fly back to Washington with the bodies of their colleagues, then resume their mission in Sarajevo with a reconstituted team “as soon as it is appropriate to do so. . . . Meanwhile we will use diplomatic channels in Belgrade, Zagreb and Sarajevo to keep the dialogue open.”

Bosnian President Alija Izetbegovic offered his condolences at the U.S. Embassy.

The diplomats “were on their way here to serve us in trying to find the true path to peace,” he said before meeting privately with Holbrooke.

The Mt. Igman route, a winding goat track that hugs the forested mountainside, is the only road into besieged Sarajevo that is not controlled by Serbian separatists. But it is within Serbian artillery range and is routinely shelled.

U.N. and U.S. officials said there was no indication that the American party came under Serbian fire. They said the armored personnel carrier apparently plunged off a muddy section of the road weakened by recent rains.

“It was a strict road-traffic accident,” U.N. spokesman Alexander Ivanko said in a telephone interview from Sarajevo. “It happened way up toward the top [of Mt. Igman], not the area where there’s a lot of firing.”

U.N. officials initially thought that the vehicle had struck land mines as it rolled down the hill, but U.S. officials said after an investigation that there was no sign of land mines.

State Department officials said the vehicle had moved to the soft shoulder of the road to avoid an oncoming U.N. convoy when it slipped off and rolled down the steep slope.

The last mile or so of the road, as it nears Sarajevo, is so dangerous that many U.N. drivers refuse to navigate it. Those travelers who do often have to drive at breakneck speed to avoid being hit by Serbian mortars. At least as many people have been killed by accidents as by artillery fire.

Holbrooke, Frasure and the American delegation began presenting their peace plan to the region’s leaders last week. They had held discussions with Serbian President Slobodan Milosevic in Belgrade and Croatian President Franjo Tudjman in Zagreb. The talks with Izetbegovic were to complete the round.

Frasure was involved last May in tough negotiations with Milosevic, who was being offered relief from international economic sanctions in exchange for his recognition of Bosnia-Herzegovina. Such recognition is considered key to ending the war, but Milosevic pressed more and more demands until Frasure finally broke off the talks, according to officials familiar with the talks.

The loss of Frasure’s expertise and his familiarity with the players in the Balkans--especially the enigmatic Milosevic--will prove costly.

The Clinton Administration had placed great hopes on this new peace drive, and any momentum it might have been gaining was stopped short with Saturday’s deaths.

Nevertheless, Clinton predicted the accident will “intensify” the search for a diplomatic solution.

“I expect them to return home with their comrades, and, after a few days, to return to press the peace mission again vigorously,” he said of the diplomatic delegation. “I am encouraged by the determination of their colleagues to carry on.”

State Department spokesman David Johnson, noting that the three men were deeply involved in shaping the U.S. peace proposals and trying to get Balkan leaders to accept them, said their loss will hinder the American peace effort. “It’s certainly going to make it more difficult to carry on our diplomacy,” he said.

The setback comes at an especially awkward time for Clinton, who faces likely efforts in Congress after Labor Day to override his veto of a move to end American observance of a U.N. arms embargo on Bosnia.

Frasure, a decorated, 21-year Foreign Service officer, was born in Morgantown, W. Va., and studied at West Virginia and Duke universities and the London School of Economics.

He had served in Switzerland, Germany, Britain, Nigeria, Ethiopia and, most recently, Estonia, where he was the U.S. ambassador before his assignment to peace efforts in the Balkans.

Times staff writer Paul Richter in Jackson, Wyo., contributed to this report.