In the first ever Knesset address by a British prime minister, Gordon Brown on Monday condemned Iranian President Mahmoud Ahmadinejad's call for the destruction of Israel as "abhorrent," and vowed that Tehran's bid to acquire nuclear weapons would not be allowed to pass.

It is "totally abhorrent for the president of Iran to call for Israel to be wiped from the map," Brown told lawmakers. "Iran has a clear choice to make: suspend its nuclear weapons program and accept our offer... or face isolation... not just of one nation, by all nations around the world."

The British leader hailed Israel's successes in the 60 years since its establishment as the manifestation of "boundless capacity of mind and spirit," adding that "no other country has accomplished as much in such a short time."

He condemned recent efforts by British unions to implement a boycott against Israel on the grounds of its treatment of the Palestinians.

"The British government will stand full square against any boycotts of Israel or Israeli academic institutions," he said.

Brown also voiced his support for the Israeli-Palestinian peace process, relaunched at a U.S.-hosed summit in Annapolis, Maryland last year, telling the Knesset that he felt "a historic and lasting peace is within your grasp." He added that he favored a two-state solution with a Palestinian state that "accepts Israel as a friend and a neighbor."

Prior to Brown's address, Prime Minister Ehud Olmert welcomed the visiting premier and also stressed that Israel could not reconcile with a nuclear Iran.

"From our point of view, we are talking about an intolerable situation, one with which we cannot reconcile ourselves," Olmert said.

He added however that Iran was not just a menace for Israel, but a "global threat."

"The state of Israel is not asking for anything else but peace," he said, adding that although Israel's conflict with the Palestinians was "bitter," it was "not unsolvable" and that although there were "still profound disagreements" in the Israeli-Palestinian peace negotiations, these were "bridgeable."

Olmert also praised Britain's "tough stance" in the global struggle against terrorism.

The United States, Britain, France, Germany, Russia and China have offered Iran financial and diplomatic incentives to halt nuclear activity which the West fears is a cover for making bombs. Tehran says its nuclear program is aimed solely at generating electricity.

After talks in Geneva ended in a stalemate on Saturday, the six major powers gave Iran two weeks to answer calls to rein in its nuclear activities or face tougher sanctions.

Rice: Iran wasn't serious at Geneva nuclear talks

Speaking of the talks in Switzerland, U.S. Secretary of State Condoleezza Rice on Monday accused Iran of not being serious, despite the presence of a senior U.S. diplomat, and warned it may soon face new sanctions.

In her first public comments since Saturday's meeting, Rice said Iran had given the run-around to envoys from the group of "five plus one" ? the five permanent members of the UN Security Council and Germany.

"We expected to hear an answer from the Iranians but, as has been the case so many times with the Iranians, what came through was not serious," Rice told reporters aboard her plane as she flew to the United Arab Emirates.

"They can't go and stall and make small talk about culture, they have to make a decision", she said. "People are tired of the Iranians and their stalling tactics."

British government officials traveling with Brown said if Iran did not accept the incentives, the next step would be to ratchet up sanctions against Tehran, possibly including sanctions on Iran's oil and gas industry.

They said such sanctions could seek to target Iran's domestic energy market by making it difficult for Iran to obtain equipment and spare parts for its refineries.

Tensions between Iran and the West have helped drive up crude oil prices to record highs in recent months.

Speaking to reporters on Sunday evening, Brown said Iran had broken the terms of the nuclear Non-Proliferation Treaty and had "misled the international community about the scale of their preparations for weaponry."

The United States has refused to rule out military action against Iran if diplomacy fails to resolve the nuclear row.

Israel, long assumed to have nuclear arms, has sworn to prevent Iran from obtaining atomic weapons. An Israeli air force drill last month raised speculation it was planning an attack.

A senior Iranian official was quoted this month as saying Iran would destroy Israel and 32 U.S. military bases in the Middle East if the Islamic Republic was attacked.