UNITED NATIONS — Diplomats involved in negotiations on new U.N.-authorized sanctions against Iran say that, in a surprising reversal, America is now seeking a broad Security Council consensus and quick action, while countries such as France are calling on Washington to toughen up and take a harder line against Tehran.

Meanwhile, Israel introduced a long-range drone that, according to press reports, can bolster the Jewish state’s arsenal against Iran. But Israel’s deputy defense minister, Ephraim Sneh, said yesterday that the sanctions against Iran are effective and that further pressure is needed. He declined to talk about military options.

“We are not talking about soft diplomacy here,” Mr. Sneh told The New York Sun in a telephone interview. “We are talking about economic measures with real teeth.”

He specifically cited American-led banking sanctions that have eroded Iran’s credit standing, as well as measures that narrow Iranian access to imported refined petroleum. Iran, he noted, exports oil, but 40% of the fuel it uses is imported from other countries.

The American diplomat who leads the negotiations on Iran, Undersecretary of State Nicholas Burns, told U.N. reporters on Monday that while Tehran is currently “quite isolated,” it is important to signal to the Iranians that “the offer to negotiate is still on the table.”

Several Security Council diplomats said this week that the American negotiating style and tactics have changed significantly since last December, when the council passed an unprecedented resolution that imposed mild sanctions on Iran and called on the International Atomic Energy Agency to report on compliance.

One reason for the shift, according to two diplomats who spoke on condition of anonymity, may be the departure of the hawkish American U.N. ambassador, John Bolton, who was the hard-liner among Washington’s diplomats.

Mr. Bolton says the fractured Security Council, where Russia works hard to protect Iran from any significant punishment, is only one weak venue for applying pressure on Iran. Council negotiations are a “tough slog,” Mr. Bolton told the Sun and are an effective tool against Iran only “as long as we’re not trapped into it being exclusive.”

According to a European official who was involved in the talks and who cited diplomatic protocol in asking for anonymity, America is “not pushing as hard as in the past” in the council’s backroom negotiations.

In the past, the diplomat said, “America would push for strong measures, Russia and China would resist, and we, the Europeans, would then broker a deal.” Currently, he said, while France supports such measures as a complete arms embargo against Iran, America makes no such demand.

Another Western diplomat said that while America supports the arms embargo, it does not insist on it. “Usually, the Americans demand,” the diplomat said. “Now, they are suggesting.”

Council negotiations are expected to continue today, as Mr. Burns conducts a conference call with some fellow political directors at the foreign ministries of the leading powers on the council.

Mr. Burns told reporters that he seeks a consensus resolution in the council “in the shortest possible time.” Several diplomats said America is pushing for a vote as early as next week.

“It seems Nick Burns wants something very quickly, and he wants unanimity in the council,” the European diplomat said. “This gives the Russians and the Chinese a strong hand.” Among the five permanent council members, America, Britain, and France are calling for tough penalties against Iran, while China and Russia are urging a soft approach.

“Effective sanctions imposed by a narrow coalition are more useful than weak sanctions by a wide coalition,” Mr. Sneh said.

America, Britain, Australia, and like-minded countries could exert even greater pressure beyond the council’s mandate, he said, adding that a Russia would “undoubtedly” block such measures as a complete arms embargo by the Security Council.

U.N. sources say the council is instead considering a tightening of travel restrictions that were already imposed in December against Iranian officials involved in the nuclear program, as well as new banking and other economic measures.

American officials, as well as Mr. Sneh, say measures taken unilaterally by the U.S. Treasury Department against Iranian companies have led to a growing unrest in Tehran. Additionally, a new congressional initiative imposing even tougher unilateral American sanctions, was launched this week by Reps. Tom Lantos, a Democrat of California, and Ileana Ros-Lehtinen, a Republican of Florida.

Mr. Sneh declined to discuss the new drone, named Shoval, which was introduced yesterday by the Israeli air force.

According to Israeli press reports, the locally developed unmanned aircraft can stay in the air for 30 hours, carry a load of 2500 pounds, and travel as fast as 140 mph and as far as Iran.