RIYADH - Saudi Arabia has mustered all its diplomatic weight to coax Syria's President Bashar al-Assad to withdraw troops from Lebanon and spare Damascus sliding into the same isolation as Iraq once did, officials said on Friday.

Crown Prince Abdullah, a leader with close Syrian ties and a reputation for championing Arab solidarity, delivered a stern message to Assad on Thursday that unless he begins a withdrawal, relations with Riyadh will suffer, the Saudi officials said.

The grim warning from a traditional ally has shown the scale of international pressure on Syria and also highlighted strains in relations between Damascus and Riyadh after last month's killing of a former Lebanese premier with close Saudi links.

"Saudi Arabia does not want to see another Iraq in Syria," said one Saudi official referring to the 2003 U.S.-led invasion of Iraq that toppled Saddam Hussein.

International demands for the pullout follow last month's assassination of former Lebanese Prime Minister Rafik Hariri. Lebanon's opposition blamed Syria, which denies involvement, and organized protests that toppled Beirut's pro-Syrian government.

Hariri made his fortune in Saudi Arabia, took Saudi citizenship and remained close to the royal family. His sons who run Hariri's business in the kingdom spent two days in Riyadh accepting condolences, including from the crown prince himself.

"Hariri was very close to Saudi Arabia. Whoever killed him knew it," said a Saudi official.

"We took it as a slap in the face."

Hours after his talks in Saudi Arabia, Syria said Assad would address parliament in Damascus on Saturday. A Lebanese political source said he was expected to announce the pullout of some troops and redeployment of others towards the border.

Assad told Time magazine in an interview published this week that Syria's 14,000 troops might leave in the next few months.

Saudi Arabia's Foreign Minister Prince Saud al-Faisal has said the world should not rush to accuse Syria of involvement in Hariri's killing, but the Saudi official said on Friday that ties with Damascus were cooling even before the bombing.

"If you go back several months you will see Saudi Arabia had distanced itself from Syria," he said.

Saudi Silence

When the United Nations Security Council called for all foreign forces to pull out of Lebanon in September last year, Saudi Arabia offered no support to Damascus.

"Saudi Arabia kept silent, kept its distance. It did not oppose the resolution," the official said.

Analysts said Saudi Arabia's falling out with Syria also reflects a wider realisation by Arabs that they cannot fight intense U.S. pressure on Syria over its military presence in Lebanon and alleged support for the insurgency in Iraq.

"No one in the region now can ignore what America is dictating, and the American tone is quite strong," said Jeddah-based political analyst Abdullah Hamidaddin.

"If Europe with all its power cannot ignore the United States, then how can the Arabs?"

Syria's withdrawal is also a key demand of Lebanon's opposition politicians.

A Saudi official said after Thursday's meeting between Assad and Prince Abdullah that Syria knew it had to pull out troops.

"They know what they should do. They should withdraw immediately," he said. "This is what we told them and this is what the whole world is telling them".