A Syrian honorary consul in the United States has resigned in protest after last week's killings in Houla, where more than 100 people were slaughtered in a massacre blamed on pro-government forces.

The resignation of Hazem Chehabi, who had helped arrange passport and other services in California, came as several countries expelled Syrian envoys to protest the spiraling violence of the 14-month government crackdown.

The head of Iran's powerful Revolutionary Guards on Thursday made a pointed visit to three islands in the Gulf whose ownership is fiercely disputed by Tehran and the United Arab Emirates (UAE).

Guards Commander Mohammed Ali Jafari, accompanied by his naval commander, Ali Fadavi, went to the islands of Abu Musa, Greater Tunb and Lesser Tunb to deliver a speech stressing they were Iran's "strategic and sensitive territory," the Guards' official news website said.

U.S. Secretary of State Hillary Clinton on Thursday criticized Russia's resistance to U.N. action on Syria, warning that its policy could contribute to a civil war.

The Russians "are telling me they don't want to see a civil war. I have been telling them their policy is going help to contribute to a civil war," she told a mainly student audience on a visit to Copenhagen.

U.N. chief Ban Ki-moon warned Thursday of a "catastrophic civil war" in Syria after the massacre of more than 100 civilians in the town of Houla that sparked global horror and outrage.

"The massacres of the sort seen last weekend could plunge Syria into a catastrophic civil war, a civil war from which the country would never recover," he told an Istanbul forum of the U.N.-led Alliance of Civilizations initiative.

President Vladimir Putin warned Thursday that Russia's position on Syria would not shift under pressure despite the crisis likely topping the agenda during his upcoming visits to Berlin and Paris.

"Russia's position is well-known. It is balanced and consistent and completely logical," Interfax quoted Putin's spokesman Dmitry Peskov as saying.

Two U.S. tourists have been kidnapped in Egypt's Sinai peninsula by Bedouins protesting the arrest of one of their tribesmen on a drugs charge, a security official said on Thursday.

The tourists were abducted late on Wednesday near the resort of Dahab on the Red Sea, the official said, adding that talks were under way in a bid to secure their release.

A senior Kuwaiti official has slammed Iran for criticizing a Kuwaiti court ruling that sentenced four men to life in jail for spying for Tehran, newspapers reported on Thursday.

"Unfortunately, this is an act of disrespect for Kuwaiti court rulings that we highly appreciate and respect," foreign ministry undersecretary, Khaled al-Jarallah, was quoted as saying by Al-Rai newspaper.

Israel on Thursday began handing over the bodies of 91 Palestinians who were killed during anti-Israeli attacks, some of whom died over 40 years ago, officials on both sides said.

The transfer began before dawn on Thursday when Israel formally gave the bodies to the Palestinians at a location near the West Bank city of Jericho, with 79 of them immediately transferred to Ramallah, and the other 12 sent to Gaza.

A spate of bombings in Baghdad on Thursday killed at least 16 people and wounded dozens more, shattering a relative calm with the capital's deadliest violence in weeks.

Roadside bombs and explosives-packed cars detonated across a half-dozen neighborhoods in the north, south and west of Baghdad, underlining persistent security concerns even as international energy companies met in the center of the capital to bid on nationwide oil and gas exploration blocks.

Armed rebels have given the Damascus regime until noon (0900 GMT) Friday to stick to Kofi Annan's peace plan to end violence in Syria, warning they themselves will quit the truce unless the ultimatum is met.

"If the Syrian regime does not meet the deadline by Friday midday, the command of the Free Syrian Army announces that it will no longer be tied by any commitment to the Annan plan ... and our duty will be ... to defend civilians," a FSA statement said.