President Mohammed Morsi has ordered Egypt's army from Monday to take on police powers -- including the right to arrest civilians -- in the run-up to a vote on a constitution that has triggered bloodshed.

The decree takes effect on the eve of mass rival protests on the referendum that is to be staged on Saturday, and follows street clashes that have left seven people dead and hundreds injured.

Rebels led by the radical Islamist group Al-Nusra Front seized a strategic army base in the northern Syrian province of Aleppo on Monday after weeks of fierce fighting, a watchdog said.

It was the last major military base west of Aleppo remaining under army control.

The Syrian military carried out an air strike on suburbs of the capital as rebels clashed on the ground with soldiers on Monday, a monitoring group said.

"A fighter bomber carried out a raid on Daraya as rebels and soldiers fought on the ground, while artillery bombed Moadamiyet al-Sham," said the Syrian Observatory for Human Rights, referring to two towns south of Damascus.

Egyptian Islamist movements, including President Mohamed Morsi's Muslim Brotherhood, will hold a rival demonstration on Tuesday, the same day as protests organised by the opposition, a Brotherhood spokesman told Agence France Presse.

A coalition called the Alliance of Islamist Forces "is calling for a demonstration Tuesday under the slogan 'Yes to legitimacy'," in support of a constitutional referendum championed by Morsi, Mahmud Ghozlan said.

The Friends of Syria nations that support regime change meet in Morocco on Wednesday for the first time since the creation of a new opposition coalition seeking wider international recognition.

Arab and Western states will consider two key issues concerning the 21-month conflict -- the political transition in the event of President Bashar Assad's fall, and mobilizing vital humanitarian aid as winter sets in.

Tunisia's main labor union has won key support for a rare nationwide general strike to be held next week from the International Trade Union Confederation, a local ITUC official said on Sunday.

ITUC secretary general Sharan Burrow will arrive in Tunis on Tuesday at the head of a delegation "to express her support for the UGTT general strike that will be observed on December 13," ITUC spokesman in Tunisia Ghassen Ksibi said.

The party of Tunisian President Moncef Marzouki could pull out from the coalition government amid tensions with the ruling Islamist Ennahda party, the secretary general of the CPR warned on Sunday.

"The Congress for the Republic will quit the government if its proposals and those of President Moncef Marzouki are not taken into account," the party's secretary general Mohamed Abbou told reporters.

Hamas chief-in-exile Khaled Meshaal, on the third day of a trip to Gaza, told students that different situations called for different measures -- from rockets to a truce.

He also renewed his call for efforts to implement a stalled Palestinian reconciliation deal between his Hamas faction and bitter rival movement Fatah, which is led by president Mahmoud Abbas.

Arab League chief Nabil al-Arabi hoped on Sunday that the United States and Russia could reconcile their views over Syria in order to facilitate a settlement of the crisis in the war-ravaged country.

"Talks between the United States and Russia along with the international envoy (Lakhdar Brahimi) continued in Geneva today," Arabi told a meeting of the Arab ministerial committee on Syria held in Doha.

Syria's rebel ambassador to France warned Sunday that the "passivity" of the international community was boosting the rise of Islamist extremists in his war-torn country.

Monzer Makhous, named last month as the Syrian opposition National Coalition's envoy to Paris, also called in a newspaper interview for the weapons embargo to be lifted so rebels could better arm themselves.