March 10 (Bloomberg) -- Saudi Arabia’s King Abdullah will meet tomorrow in Riyadh with Syrian President Bashar al-Assad, a week after the kingdom called for Arab unity to confront the threat from Iran, a traditional ally of Syria.

Abdullah, who will also meet Egyptian President Hosni Mubarak, will discuss with Assad “bilateral relations as well as regional and international topics,” the state-owned Saudi Press Agency reported.

Saudi Foreign Minister Prince Saud al-Faisal told an Arab League foreign ministers meeting in Cairo on March 3 that Arab countries needed to work together in the face of the “Iranian challenge” to the Gulf’s security. Saudi Arabia, which has had tense ties with Syria for years, is seeking to forge a common front before an Arab League leaders’ summit in Qatar this month and isolate Iran.

“Syria is a long-standing ally of Iran in the Arab world,” said Mustafa Alani, a regional security expert at the Gulf Research Center in Dubai. “As long as Syria isn’t part of this Saudi effort, there won’t be any strong Arab unity.”

Saudi Arabia, a largely Sunni Arab country, is worried at the rising regional influence of Shiite Iran, which has ambitions to be the main power in the Gulf, said Alani.

Syria most recently clashed with Saudi Arabia during the Israeli offensive in Gaza, by taking the side of Palestinian militant group Hamas. Syrian support for Hamas as well as Lebanese radical Islamic group Hezbollah, in collaboration with Iran, has been an irritant to Saudi Arabia.

A day after the Saudi warning against Iran in Cairo, Faisal met Assad in Damascus and invited the Syrian leader to Riyadh.

“The flurry of diplomatic visits, including an upcoming trip by Syrian President Bashar al-Assad to Saudi Arabia, indicates the progress so far in this gradual Syrian-Saudi rapprochement,” U.S.-based risk consultancy Stratfor said in an e-mailed commentary.

The warming of relations between Saudi Arabia and Syria comes “as Riyadh seeks ways to deprive Iran of a key ally,” it said.

To contact the reporters on this story: Henry Meyer in Dubai at hmeyer4@bloomberg.net; Glen Carey in Dubai at gcarey8@bloomberg.net

Last Updated: March 10, 2009 10:38 EDT