Saudi Arabia strongly criticized Egyptian protesters and voiced support for beleaguered Egyptian President Hosni Mubarak on Saturday, appearing to underscore growing concern across the Arab world over possible spill-over from popular protests that have ousted Tunisia´s long-time strongman and now threaten Mr. Mubarak´s grip on power.

In a statement carried by Saudi´s state news agency, King Abdullah bin Abdulaziz al-Saud said protests rocking Egypt were instigated by "infiltrators," who "in the name of freedom of expression, have infiltrated into the brotherly people of Egypt, to destabilize its security."

The king said protesters had been "exploited to spew out their hatred in destruction . . . inciting a malicious sedition,´´ according to the statement, posted on the English website of the Saudi Press Agency.

The statement said the king telephoned Mr. Mubarak early Saturday and had been "reassured about the situation in Egypt." Saudi Arabia and Egypt have been strong allies in the region, representing two of the most important U.S.-allied Arab bulwarks against Iran.

In the wake of the Tunisia unrest, several Arab regimes, including Jordan and Yemen, have also been rocked by large protests. Those demonstrations and the ones now buffeting Egypt have raised the specter of protests spreading wider, including to the relatively wealthy, but still-authoritarian, Arab regimes of the Persian Gulf.

The king´s harsh criticism of the Egyptian protesters on Saturday suggested Riyadh is eager to signal it won´t tolerate unrest inside the kingdom´s own borders.

Saudi´s oil wealth has allowed Riyadh to insulate the Saudi population to some degree from the economic ills that have helped trigger the recent regional unrest. Flush with oil revenues, Saudi has embarked on a massive infrastructure and development splurge, including plans for giant new cities aimed at creating jobs for its ballooning youth.

Iranian officials, meanwhile, voiced continued support on Saturday for demonstrators in Egypt. The Shiite-led Iranian government in Tehran has long been at odds with its neighboring Arab states, in particular Mr. Mubarak´s Egypt.

A spokesman for the Iranian Foreign Ministry said Saturday that Tehran expected Egypt to "respond to (protesters´) rightful demands and refrain from exerting violence," according to Press TV, Iran´s English-language state media. Write to Chip Cummins at chip.cummins@wsj.com (Copyright © Dow Jones & Company, Inc.) 01/30/11)