Al-Qaida in Yemen has beheaded three Yemenis in the country's eastern province of Marib, accusing them of "spying" for the government, the ministry of defense said on Tuesday.

The "bodies of two Yemeni nationals ... were found with their heads severed," the ministry, citing a local official, said in a statement posted on its website. It said that officials were looking for the third body.

NATO head Anders Fogh Rasmussen warned Tuesday against the dangers of the conflict in Syria escalating, saying alliance member Turkey had shown commendable restraint in response to shelling of its border area.

"I would like to commend the Turkish government for the restraint it has shown in its response to the completely unacceptable Syrian attacks," Rasmussen said as he went into a two-day NATO defense ministers meeting.

Libya has already gathered "considerable' evidence to prosecute the son of slain Libyan leader Moammar Gadhafi for crimes against humanity, a lawyer told the International Criminal Court on Tuesday.

The domestic investigation "has already produced considerable results," Philippe Sands said at a two-day hearing to decide where Seif al-Islam should face justice.

U.N. Secretary General Ban Ki-moon on Tuesday urged the Syrian regime to declare an immediate truce to bring an end to the conflict that he said had left 20,000 dead over the last 19 months.

"It is unbearable for the (Syrian) people to continue like this. That is why I have conveyed to the Syrian government (a) strong message that they should immediately declare a unilateral ceasefire," he said.

Iran's foreign ministry warned on Tuesday it could look at cutting diplomatic ties with the United Arab Emirates because of a festering dispute over three Gulf islands claimed by both countries.

"If making such anti-Iranian claims reaches a level that national interests lie in reducing or severing political ties... (such a move) will be implemented after consultations with experts," ministry spokesman Ramin Mehmanparast told the parliamentary news website icana.ir.

Twin suicide bombings hit a Syrian air force compound near Damascus killing dozens of people on Tuesday, monitors said, as rebels took a key town on the road between the capital and second city Aleppo and regime troops stormed a key rebel district of the central city of Homs.

Turkey, meanwhile, again warned Syria it would not hesitate to retaliate for any strike on its soil as the country's top military commander visited troops stationed along the reinforced border.

Turkey's top military commander General Necdet Ozel on Tuesday inspected troops in the southeastern Hatay province near the Syrian border, a day after a Syrian shell landed in a nearby town, local media reported.

Ozel inspected military units in the province and was expected to tour the border region, which has been shuttered over the past week with tanks and anti-aircraft missiles, reported the Anatolia news agency.

More than 70 Palestinian olive trees were uprooted overnight near the northern West Bank city of Nablus in an attack blamed on Jewish settlers, local officials and an Agence France Presse journalist said.

Residents of Qaryut village 15 kilometers south of Nablus blamed the attack on settlers from the neighboring settlement of Eli.

A suicide attacker detonated a car bomb near a compound of the Syrian intelligence on the outskirts of Damascus on Monday, a Syrian official said.

There were no immediate reports of casualties in the blast in Harasta, a suburb of the nation's capital, said the official, speaking on condition of anonymity because he was not authorized to speak to the media.

Egypt's President Mohammed Morsi on Monday pardoned all those arrested between the start of the revolution that toppled president Hosni Mubarak in February 2011 and June this year, state media said.

A decree published on the presidency's official Facebook page announced the amnesty for deeds "committed with the aim of supporting the revolution and bringing about its objectives, in the period January 25, 2011 to June 30, 2012, with the exception of crimes of first-degree murder."