JERUSALEM - Visiting British Prime Minister Gordon Brown on Monday said his country would remain at the forefront of efforts to block Iran from obtaining nuclear weapons, directly addressing one of Israel's greatest fears.

Speaking to Israel's parliament in the first-ever address there by a British premier, Brown said Iran must either halt its program or face international isolation.

"It is totally abhorrent for the President of Iran to call for Israel to be wiped from the map of the world," Brown said. "The U.K. will continue to lead -- with the U.S. and our EU partners -- in our determination to prevent an Iranian nuclear weapons program."

Israel considers Iran to be its most dangerous enemy. It does not believe Iran's claims that its nuclear program is peaceful, and takes seriously Iranian President Mahmoud Ahmadinejad's repeated calls to wipe the Jewish state off the map.

Challenging one of Israel's sacred precepts from the heart of its legislature, Brown said peace should be built on the principle of an independent Palestinian state living peacefully alongside Israel, "with Jerusalem the capital for both."

Israel captured east Jerusalem, where more than 200,000 Palestinians live, in the 1967 Middle east war and swiftly annexed it, declaring the entire city its "eternal and indivisible" capital.

The Palestinians claim the east side as the capital of their future state.

Brown's address in Parliament Monday echoed a call made last month from the same podium by French President Nicolas Sarkozy, and reflected current EU thinking.

The U.S. defines the future status of Jerusalem as an issue to be decided in negotiations between the Israelis and the Palestinians.

In 1995, Congress recognized Jerusalem as the capital of Israel and ordered the U.S. embassy to move there from its present location in Tel Aviv but successive U.S. administrations suspended the relocation of the embassy, citing national security concerns.

In a speech welcoming Brown to the legislature Monday, Israeli Prime Minister Ehud Olmert said that after eight months of peace talks with the Palestinians, major gaps remained.

"There are still deep disagreements on decisive issues," he said. "But they can be bridged."

Brown arrived Saturday night on a two-day visit to Israel and the Palestinian territories, his first as Britain's leader. He was due to depart after the speech to parliament.

On Sunday he met Palestinian leaders in the West Bank town of Bethlehem, where he told reporters that Israel must stop construction on Jewish settlements.

Israel and the Palestinians resumed peace talks last November at a U.S.-mentored conference in Annapolis, Md. Both sides had originally aspired to reach a final peace deal by the end of the year, but have backed away from that goal because of arguments over settlements and whether the Palestinians are capable of enforcing security in areas they control.

Brown spoke of the "deep affection for Israel" instilled in him as a child by his father, a Church of Scotland minister who spoke Hebrew and led groups of pilgrims to the Holy Land.

"For the whole of my life I have counted myself as a friend of Israel," he said, pledging to bring his own young children on a visit in their grandfather's footsteps.