Public security in Tunisia was "normal throughout the country" ahead of Friday prayers, after which several religious groups had planned protest rallies, an interior ministry spokesman said.

At the last minute Thursday, fundamentalist Islamic groups and the moderate Muslim Ennahda party in power called off the rallies they had planned to hold following Friday prayers, after the government issued a ban.

The U.N. observer force on Friday accused both sides in the Syrian conflict of hampering its peace mission and admitted its limitations in the face of escalating violence.

France, meanwhile, said that world powers could hold a summit on the Syrian crisis as the deadly anti-regime revolt entered its 16th month.

A controversial court decision on the eve of Egypt's second round presidential vote gives the nation's army the means to keep its key political role and challenge the Muslim Brotherhood, analysts say.

The constitutional court's decision on Thursday to invalidate parliament on the grounds that a third of its members were elected illegally was a blow for Islamists, who currently dominate the house but stand to lose ground in any new election.

The number of Syrian refugees registered in Turkey has topped 30,000, a Turkish foreign ministry official told Agance France Press on Friday.

"Four hundred more Syrians crossed into Turkey on Thursday, bringing the total number to 30,800," said the official, who wished to remain anonymous.

At least 26 people were killed in violence on Friday as thousands protested against the regime across Syria, activists and a monitoring group said.

Activists uploaded videos of protests outside mosques or street marches on what they named a "Friday of Readiness."

More than 2,000 Jordanians braved blistering temperatures on Friday to demonstrate across the country against recent hikes in commodity prices, demanding sweeping political change and constitutional reform.

"Instead of raising prices, hold the corrupt accountable. Reform the constitution and let the people see the light," read one of the banners carried by around 1,000 protesters, including Islamists, leftists and youths, who marched in central Amman.

Syrian opposition leaders were meeting in Turkey on Friday in a bid to settle their differences and forge a united front to confront the escalating conflict in their homeland.

"We will work towards a unified vision," said Burhan Ghalioun, who stepped down last month as head of the main opposition group the Syrian National Council in the face of mounting splits that were undermining its credibility.

Syrian government forces have used sexual violence to torture men, women, girls and boys detained during the current conflict, Human Rights Watch said on Friday.

The New York-based group said it had interviewed 10 former detainees, including two women, who described being sexually abused or witnessing such abuse in detention.

The escalating bloodshed in Syria is hampering a hard-won U.N. observer force's ability to carry out its mission, its chief Major General Robert Mood said on Friday.

"The escalating violence is limiting our ability to observe, verify reports as well as assist in local dialogue and stability," the veteran Norwegian peacekeeper told reporters in Damascus.

Envoys from the Middle East Quartet met in Brussels on Friday amid calls from the Palestinians to step up action to halt continuing Israeli settlement activity.

Officials from the United States, United Nations, European Union and Russia gathered "to consult as they routinely do over the phone as well", said a spokesman for EU foreign policy Chief Catherine Ashton.