The U.N. Security Council on Wednesday extended the U.N. peacekeeping mission in Bosnia until July 15, averting a threatened shutdown by the United States over its demand for immunity for American peacekeepers from the new war crimes tribunal.

The delay gives the 15-member council more time to try resolving a contentious dispute over the International Criminal Court that has left the United States at odds with its allies and the majority of the council.

The council opted for the short extension after members rejected two compromise U.S. proposals to put American peacekeepers beyond the reach of the court — and after receiving a copy of a sharply worded letter from the U.N. secretary-general warning that the council risked "being discredited" by the U.S. proposal.

On Sunday, the United States had vetoed a resolution extending the Bosnian mission because it didn't grant immunity to American peacekeepers, but agreed to a 72-hour extension until midnight Wednesday.

U.S. Ambassador John Negroponte had vowed not to extend the mission without winning an exemption for U.S. peacekeepers.

But Negroponte said the United States gave the green light for the extension because a number of council members "saw movement in our position" and indicated an interest in continuing discussions.

"It's been an uphill fight in gaining acceptance of positions we have been putting forward," Negroponte said, but "no one has slammed the door on our proposals."

Richard Dicker, director of the International Justice Program at Human Rights Watch, said, "The U.S. climbed down, but we are in a holding pattern. The integrity of the court and treaties is at stake."

The United States is demanding immunity for U.S. participants in U.N. peacekeeping operations, saying it fears Americans could be subject to frivolous political prosecutions.

The demand has left Washington standing virtually alone against the vast majority of council members who support the court, which came into existence on Monday.

The Bush administration also has been criticized worldwide and at home for its threats to end U.N. peacekeeping in Bosnia if it doesn't get immunity.

The initial U.S. proposal would have given the council's veto-wielding members — the United States, Britain, France, Russia and China — the right to permanently block the court's investigation or prosecution of peacekeepers.

A revised proposal Washington introduced Wednesday afternoon would also allow the Security Council's permanent members to provide immunity for peacekeepers. While it changed some language, it would still deny the International Criminal Court jurisdiction over American peacekeepers.

At closed discussions Wednesday morning, diplomats said 10 of the 15 council members opposed the first U.S. proposal, and only China supported it.

Norway's U.N. Ambassador Ole Peter Kolby said the United States gained some support from council members during a discussion of the second proposal Wednesday afternoon, but "still it doesn't go far enough to be acceptable."

"They've tried, but their best isn't good enough," said Mexico's Deputy U.N. Ambassador Roberta Lajous.

In a letter to Secretary of State Colin Powell, U.N. Secretary-General Kofi Annan warned that the U.S. proposal "flies in the face of treaty law" because it amounts to an amendment of the Rome statute. No member of a U.N. peacekeeping mission has been accused of war crimes, he said, making the issue moot and threatening to discredit the council.

"The whole system of U.N. peacekeeping operations is being put at risk," Annan warned.

The United Nations has 14 other peacekeeping missions, from East Timor and the Middle East to Kosovo and Congo, and in addition to Bosnia, four others are up for renewal in July.

The Security Council had been seeking a six-month extension of the 1,500-strong U.N. police training mission in Bosnia, which was due to be handed over to the European Union on Jan. 1. The resolution would also have extended U.N. authorization for the 18,000-strong NATO-led peacekeeping force in Bosnia for one year.

The United States appeared to be giving ground, at least as far as the NATO force is concerned.

Air Force Gen. Richard Myers, chairman of the U.S. Joint Chiefs of Staff, told reporters at NATO headquarters in Brussels on Wednesday that the U.S. commitment in Bosnia would not be affected by the dispute. "It's in together, out together," he said.

More than 100 nations held an open meeting at U.N. headquarters Wednesday to express dismay at the U.S. proposal and later sent a letter to council members urging that they respect the court's independence.

A European diplomat said European Union nations were "very, very firm" in supporting the court and opposing any proposals that distort its "spirit and letter."

The court, which will prosecute those responsible for genocide, crimes against humanity and war crimes on or after July 1, will step in only when countries are unwilling or unable to dispense justice. Supporters say this and other safeguards will prevent the frivolous prosecutions feared by the United States.