Prince Abdullah is gathering international support for his plan

There was no immediate Syrian statement on the talks.

The BBC's Heba Saleh, reporting from Cairo, Egypt, says Mr Assad was probably in Saudi Arabia to seek assurances that Prince Abdullah's proposals took account of Syria's concerns, chief among which is the return of the Golan Heights, occupied by Israel in 1967.

Syria is a key front line state, she says, and its backing is crucial for the success of the initiative.

The plan has already won much international support, but Arab countries such as Lebanon have voiced reservations, while Libya and Iraq have rejected the proposals outright.

Refugee question

Mr Assad held talks with Lebanese leaders on Sunday - becoming the first Syrian leader to visit Beirut since 1947.

The two countries want any peace plan to include the right of Palestinian refugees to return to their land.

Some 3.6 million Palestinians have been displaced as a result of Israel's creation in 1948.

Mr Assad, like his father before him, has insisted that there can be no compromise on the right of Palestinians to return to their land.

Prince Abdullah has described his proposals as offering a "fair and just solution" for the Palestinian refugees.

He has talked to several world leaders about the details in recent days and Egyptian President Hosni Mubarak is in Washington discussing the plan with US leaders.