British Foreign Secretary William Hague said on Saturday there is evidence that the Syrian government could use its chemical weapons stocks in its conflict with rebels fighting to oust it.

"We are extremely concerned about the stockpiles of chemical and biological weapons, and we are also concerned about evidence during the last couple of weeks that the regime could use them," Hague told reporters in Manama on the sidelines of a regional security conference.

Calm was restored to Egypt on Saturday as the powerful military threw its weight behind dialogue to resolve the political crisis dividing the nation, warning it would "not allow" events to take a "disastrous" turn.

A mass overnight protest against President Mohammed Morsi ended peacefully, but the underlying political crisis dividing the country persisted.

Syrian troops battled rebels near Damascus on Saturday leaving four fighters dead as the army bombarded opposition strongholds in the south of the capital and on its northeastern outskirts, a watchdog said.

The four rebels were killed in clashes around government offices between the towns of Harasta and Irbin northeast of Damascus, the Syrian Observatory for Human Rights said.

Egyptian authorities have detained a suspected terror network ringleader whose operatives are believed to have carried out a deadly attack on a U.S. mission in Libya, a report said Friday.

Mohammed Jamal Abu Ahmed -- a former member of the Egyptian Islamic Jihad, who was freed from prison in March 2011 following the ouster of Egyptian leader Hosni Mubarak -- was captured in the past week, the Wall Street Journal reported, citing unnamed U.S. officials.

Bahraini Crown Prince Salman bin Hamad al-Khalifa on Friday called on for dialogue with the mainly Shiite Muslim opposition in the Sunni-dominated country, urging them to condemn violence.

"We had our own experience of the so-called Arab Spring last year. It divided the nation, and many wounds are still to be healed," the prince told delegates at the annual Manama Dialogue organized by the International Institute of Strategic Studies.

A prominent opposition leader on Friday stressed preconditions for any dialogue with President Mohamed Morsi to ease Egypt's dire political crisis, notably that Morsi postpone a referendum on a new constitution.

Mohamed ElBaradei, a former U.N. atomic agency chief and Nobel peace prize winner, also called on Morsi to "repeal the decree" announced two weeks ago giving him sweeping new powers, saying "he can do this immediately, tonight."

The United Nations is strengthening its force monitoring a ceasefire between Syria and Israel because of the growing threat from the Syria conflict, a top U.N. official said Friday.

U.N. peacekeeping chief Herve Ladsous said extra armored cars would be sent to the force in the strategic Golan Heights where tensions have escalated in recent months as the civil war spreads.

Tunisian President Moncef Marzouki has denounced arms trafficking in North Africa since the fall of Libyan dictator Moammar Gadhafi, a particular source of concern given the current strife in Mali.

The Gadhafi "regime accumulated weapons, and now some are in the hands not only of Islamists from Libya, but also from Algeria and Tunisia," Marzouki said in an interview with The World Today, edited by London-based think tank Chatham House.

The world chemical weapons watchdog has asked Syria to sign up to a convention banning their use, expressing "serious concerns" that for the first time in the agreement's history they might be used.

The announcement by the Organization for the Prohibition of Chemical Weapons (OPCW) came amid speculation that Syria is considering using chemical weapons in its war with rebel forces.

U.N. human rights chief Navi Pillay on Friday criticized Egypt's draft constitution and expressed sympathy for those protesting the way it had been drawn up.

"I believe people are right to be very concerned," Pillay said Friday, pointing to "the way the process has been short-circuited," as well as "some of the elements included in, or missing from, the draft text."