Syria must choose between `peace or belligerence` in its dealings with Israel, and between relations with Iran or the Jewish state, Israeli President Shimon Peres said Wednesday.

`They cannot escape the choice... they are under the impression that they can do both,` the former prime minister and Nobel peace prize winner said during a visit to London.

`They have to make up their mind. It`s either peace or belligerence,` Peres told reporters at a briefing.

`If they think they can make the peace with Israel and maintain their close relations with Iran and (Lebanese militant group) Hezbollah, they will discover` that is not possible, he said.

No potential American mediator -- which Syrian President Bashar Al-Assad has called for -- would agree to Syria negotiating peace with Israel while maintaining close relations with Iran, said Peres.

`I don`t see an American (mediator) that will agree to do the two things -- to help the Syrians on agreeing the land (issue), and keep a very close relationship with the Iranians.`

The Syrian president last week called on Israel to prove it was interested in forging a peace deal, six months after the long-time foes relaunced indirect negotations.

Talks between the two countries needed `international patronage,` chiefly from the United States, he said.

Direct negotiations were frozen eight years ago after Israel baulked at Syrian demands for the return of the whole of the occupied Golan Heights, right down to the Sea of Galilee, its main water source.

Israel seized the Golan Heights in the 1967 Middle East war, annexing it in 1981 in a move never recognised by the international community.

Later on Wednesday, Peres addressed both houses of Britain`s parliament for the second time -- he previously gave a speech to the House of Commons and House of Lords in January 1986.

Addressing both houses is a rare honour that has only been conferred on 34 individuals, including Peres, since 1939, including Nelson Mandela, Mikheil Gorbachev, the Dalai Lama, Ronald Reagan and, most recently, Nicolas Sarkozy.

Other highlights of Peres`s visit to Britain include an audience with Queen Elizabeth II plus talks with Prime Minister Gordon Brown and Foreign Secretary David Miliband Thursday.

Earlier on the trip, he addressed students at the prestigious Oxford University, though protesters attempted to shout him down, according to British media.