President Moncef Marzouki on Thursday ruled out the risk of Tunisia's elected authorities being deposed, after Egypt's army ousted its head of state, while stressing the need to "pay attention" to popular demands.

"Could Tunisia witness the same (Egyptian) scenario? I don't think so, because it's missing the fundamental ingredients. Here we have a professional, republican army that has never got mixed up with politics," he said.

Russia on Thursday blocked a U.N. Security Council demand that Syria allow immediate access to thousands of civilians trapped by a government offensive on the city of Homs, diplomats said.

Diplomats said Russia's opposition to the statement proposed by council members Australia and Luxembourg was a new sign of a growing international split over the 26-month old conflict.

Two Yemenis condemned to death for forming an armed gang and for robbery were executed in the Saudi capital on Thursday, the interior ministry said.

In a statement cited by the official SPA news agency, the ministry said the two were the leaders of a gang whose other members have been sentenced to flogging and prison terms.

Syria's main opposition said Thursday that the fall of the city of Homs to regime forces could scupper any hope of a political solution to the civil war.

The fall of rebel strongholds in Homs, a symbol of the revolt against President Bashar Assad's rule, would make any talks with the regime unpalatable to too many Syrians, spokesman Khaled Saleh said.

Egyptian military police on Thursday arrested Muslim Brotherhood supreme guide Mohammed Badie, a security official said, as authorities rounded up members of the influential group from which ousted president Mohammed Morsi hails.

Badie "was arrested in (the western city of) Marsa Matrouh at the request of the prosecution for inciting the killing of protesters," the official told Agence France Presse.

A movement called Tamarod has launched a petition to have Tunisia's National Assembly dissolved, in a campaign similar to the one in Egypt that led to the army ousting the president, one of its organizers said Thursday.

"We don't want any support from the political parties to protect our credibility," Mohamed Bennour told Agence France Presse.

Families separated for almost four decades by the conflict in Western Sahara will be reunited, often for the first time, by the expansion of a U.N. program for refugees living in camps near Tindouf, Algeria.

An agreement reached in Geneva between Morocco, Algeria, Mauritania and Western Sahara guerilla group the Polisario Front will initiate a new flight schedule to ferry refugees to their families and vice versa for 2014.

NATO Secretary General Anders Fogh Rasmussen on Thursday called for a quick return to civilian government in Egypt.

"I am gravely concerned by the situation in Egypt and ... reports of fighting and deaths" given the country's "vital role" in the region, Rasmussen told a news conference.

A Libyan military helicopter crashed during an airshow in the eastern city of Benghazi on Thursday killing two crew members and wounding a third, an airforce official told Agence France Presse.

The accident occurred while a military parade was underway at the Benina airbase in Benghazi, Libya's second city and cradle of the 2011 uprising that toppled dictator Moammar Gadhafi.

French President Francois Hollande arrived Thursday in Tunisia, birthplace of the Arab Spring uprisings that is battling political instability and ruled by an Islamist-led government, for talks expected to be dominated by events rocking Egypt.

Presidential spokesman Romain Nadal said that during his visit Hollande was "naturally ready to discuss" the situation "in Egypt, Libya and Syria", other Arab countries swept by popular uprisings.