Saudi Arabia would sit down with Israel at a US-proposed Middle East peace conference, provided it dealt with matters of substance, Saudi officials said today.

The Saudi foreign minister, Saud al-Faisal, said Riyadh welcomed the American initiative after he emerged from talks with the US secretary of state, Condoleezza Rice, who was in the region with the secretary of defence, Robert Gates, to bolster support for Mr Bush's effort to kick-start Middle East peace talks.

Saudi Arabia has no diplomatic relations with Israel, and a conference attended by both countries would be a considerable breakthrough for US diplomacy.

Earlier this year, the Saudis revived a peace proposal that offered Israel full diplomatic ties with 22 Arab countries in return for a withdrawal from Arab territories occupied in 1967.

"I said before that we are interested in a peace conference that deals with the substantive matters of peace, the issues of real substance and not form or insubstantive issues," the Saudi foreign minister said.

"If that does so, it becomes of great interest for Saudi Arabia and should we then get an invitation from the secretary [Ms Rice] to attend that conference we will look very closely and very hard at attending the conference."

Israel said it hoped Saudi Arabia would attend such a conference.

"We hope that many Arab countries will attend this international meeting, including Saudi Arabia," said a statement from the office of the prime minister, Ehud Olmert.

Other Arab foreign ministers have given a qualified welcome to the US plan. But they want the conference to include all parties concerned, a condition that could prove a problem as the US wants to exclude Syria and Hamas, the Islamist group that seized control of Gaza in June.

Syria today said peace with Israel would only come when it returned all Syrian territory occupied during the 1967 war.

"Our desire for peace does not mean at all abandoning our rights," President Bashar Assad said in a televised speech to mark Syria's national army day. "Syria's leadership, people and military will only accept the full return of the Golan Heights."

Earlier this week, the US announced massive arms sales to certain countries in the region as part of its latest diplomatic push, with Saudi Arabia and other Gulf states set to receive $20bn (£10bn) worth of weapons, while Israel is being offered $30bn.

Ms Rice, who is now in Israel, was expected to press Mr Olmert to respond to Saudi overtures by making more concessions to the Palestinian president, Mahmoud Abbas, whose Fatah faction still controls the West Bank.

Israeli officials said Mr Olmert was prepared to discuss borders and other core issues in "general terms" that could lead to an "agreement of principles" for establishing a Palestinian state.

But Mr Olmert has not agreed to fully fledged negotiations over the three main final status issues - borders, the status of Jerusalem and Palestinian refugees - as proposed by Mr Abbas. Israeli officials said any commitment now could raise expectations and lead to further violence if talks broke down.