UNITED NATIONS — As Israel and Iranian proxy terrorist organizations escalated the war in Gaza and Lebanon, America vetoed a proposed Security Council resolution yesterday that condemned Israeli “military assaults” on Gaza and called for their immediate end. Secretary-General Annan, separately, dispatched a three-man team to mediate between the warring parties in Lebanon.

Although America blocked the major diplomatic intervention by the council, Israel’s action was roundly condemned elsewhere. Dissatisfaction that the world’s top diplomatic body was unable to address the growing Middle East crisis led some diplomats to express their concern that, though expected, yesterday’s veto might affect America’s diplomacy on other issues, including the Iranian and North Korean nuclear programs.

The European Union denounced the Israeli response to Hezbollah’s attacks in an unusually harsh rebuke, expressing its concern about “disproportionate use of force by Israel in Lebanon in response to attacks by Hezbollah.” Finland, the current E.U. president, said in a statement, “The imposition of an air and sea blockade on Lebanon cannot be justified.”

In Germany, President Bush countered: “Israel has a right to defend herself. Every nation must defend herself against terrorist attacks and the killing of innocent life.” He added, however, “Whatever Israel does, though, should not weaken the Siniora government in Lebanon.” America has “been working very hard through the United Nations and with partners to strengthen the democracy in Lebanon,” he said.

Putting the onus on Iran’s proxy militia, Mr. Bush said, “The Lebanese people have democratic aspirations, which is being undermined by the actions and activities of Hezbollah.”

At the United Nations, the American ambassador, John Bolton, said that, if adopted, the resolution proposed by Qatar “would have exacerbated tensions.” “Passage would also have undermined the credibility of the Security Council,” he added. But after trying to gather seven abstentions among the 15-member council to prevent a vote, America was obliged to veto the proposal.

Ghana and Congo supported the resolution, as did Japan, which decided that settling the North Korean nuclear standoff is more important to its national interest than confronting major powers on the Middle East. Europe split, with France and Greece supporting the resolution and Britain, Denmark, and Slovakia abstaining. Peru abstained as well.

In the end, the proposal had 10 supporters. Asked whether the veto could harm America’s stance on the council’s negotiations on North Korea and Iran, which are expected to enter a critical stage this weekend, Mr. Bolton told The New York Sun he thought it would have no effect.

“In some way it does,” said the Russian ambassador to the United Nations, Vitaly Churkin, who so far has opposed the American stance on Iran and North Korea. “Council unity” is always preferred, he said. However, he added quickly, “One should not read too much into this.”

Mr. Bolton told the council that Qatar’s proposal was “not only untimely, but already outmoded,” as events in Lebanon were unfolding so rapidly. Lebanon yesterday called on the council to urgently convene to debate the Israeli offensive. While an open meeting is scheduled for Friday, it is expected to yield little beyond heated speeches and a statement supporting the mission sent by Mr. Annan.

That mission, headed by the secretary-general’s political adviser, Vijay Nambiar, includes two other Middle East authorities who rarely see eye to eye: special envoys Alvaro de Soto and Terje Roed Larsen. Mr. Annan called on Israel last week to halt its Gaza operations and urged the council to take “a clear position” on the situation there.

In his council speech yesterday, Mr. Bolton said, “Public statements of U.N. officials must also accurately reflect positions agreed by member governments.” He did not specify, and his aides refused to say, whom the remark was directed at.