Another general has fled Syria and joined rebels camped in southeastern Turkey with plans to confront the Damascus regime, the Anatolia news agency reported Saturday.

His identity was not disclosed for security reasons.

U.N. observers suspended their mission to Syria on Saturday, blaming intensifying violence as troops reportedly rained shells down on rebel strongholds, trapping more than 1,000 families in one city alone.

The unarmed observers have been targeted almost daily since deploying in mid-April to monitor a U.N.-backed but widely ignored ceasefire, and they were likened to "sitting ducks in a shooting gallery" by Susan Rice, the U.S. envoy to the United Nations.

Saudi Crown Prince Nayef bin Abdul Aziz, a half-brother of King Abdullah, died on Saturday, the royal court said, leaving the oil powerhouse with no apparent successor to the throne.

Prince Nayef, a long-serving interior minister, "died outside" Saudi Arabia having recently left the Gulf state for medical treatment, said a statement carried by state media, including al-Ekhbariyah Television and SPA news agency.

Two car bombs targeting Shiite pilgrims in the Iraqi capital killed at least 32 people and wounded dozens more on Saturday, marring the peak day of commemorations for a revered Shiite imam.

An interior ministry official said a car bomb exploded at about 12:15 pm (09:15 GMT) on a highway near Shuala in north Baghdad, killing 14 people and wounding 32, while a second car bomb exploded at the Aden intersection near Kadhimiyah about 2:00 pm, killing 18 people and wounding 36.

More than 1,000 families were trapped on Saturday in several neighborhoods of the central city of Homs and under bombardment by regime forces, the Syrian Observatory for Human Rights said.

"More than 1,000 families, including women and children," are trapped in the Khalidiyeh, Jourat al-Shiah, Qarabees, old Homs and Qusour areas. "They have no food and no medical equipment," the watchdog's Rami Abdel Rahman told Agence France Presse.

Syrian troops shelled several rebel strongholds overnight and on Saturday, including Douma in northern Damascus and the central city of Homs, with a watchdog reporting at least 31 people killed nationwide.

Three women were among seven killed in the bombardment of the opposition bastion of Douma, the Britain-based Syrian Observatory for Human Rights said.

Syrian opposition leaders met Saturday for a second day of talks with hopes of inking the founding principles of a future Syria, now tarnished by a 16-month long bloodshed and political chaos.

Major Syrian opposition groups gathered once more in Istanbul under the umbrella of the main opposition, the Syrian National Council (SNC), recognized by most factions as the official voice, and a "legitimate representative of Syrians" by Western and Arab powers.

The U.N. Security Council expressed "serious concern" Friday over Libya's detention of four International Criminal Court officials and called on the country to work toward their release.

A Security Council statement pointedly reminded Libyan authorities that they have to cooperate with the ICC under U.N. resolutions on the conflict last year that led to the overthrow of late strongman Moammar Gadhafi.

Egyptians began voting on Saturday in the second round of a presidential election, pitting an Islamist against a former premier of the old regime amid political turmoil and with the post's powers still undefined.

Ahmed Shafiq, ousted president Hosni Mubarak's last prime minister, faces off against the Muslim Brotherhood's Mohammed Mursi in a two-day ballot in which 50 million Egyptians are eligible to vote.

Bedouins who kidnapped a Singapore tourist in Egypt's Sinai Peninsula Friday released him after several hours, a security source said.

"He was handed over to the security forces," the source said.