Clashes erupted in the Libyan capital on Friday between crowds demonstrating against militias in the city and supporters of a law to exclude Gadhafi-era officials from top government jobs, an AFP journalist said.

Several hundred people gathered in Tripoli's central Algeria Square to protest against militias that have been laying siege to the justice and foreign ministries to call for the sacking of officials from the ousted regime of Moammar Gadhafi.

Syria's Greek Orthodox faithful bore a heavy cross on Friday as they marked the crucifixion of Christ, their country ravaged by two years of war and two of their bishops missing after being kidnapped by unknown gunmen.

Good Friday is a day when even the least pious tend to join in its solemn prayers and processions, but churches in Syria's capital, no longer safe from car bombings and mortar attacks, are unlikely to be full this year.

A military mission to secure Syria's chemical arsenal would require a large ground force and pose huge risks, with the outcome hinging on the quality of Western intelligence, experts say.

With the Syrian regime suspected of using chemical agents against rebels, U.S. and Western military commanders are planning for a possible worst-case scenario in which an international force would move in to neutralize the lethal weapons.

Politicians have reached an agreement on a future political system in Tunisia, ending a months-old stalemate that had blocked progress on drafting the new constitution, the head of the ruling Islamist party said on Friday.

"We have overcome the impasse, we are heading towards a mixed regime where neither the head of state nor the head of the government will have supreme control over the executive power," Rached Ghannouchi told Tunisian radio.

The U.N. Security Council is not entitled to give the green light for inspections of Syrian refugee camps in Jordan, Russian Foreign Minister Sergei Lavrov said Friday, seeing it as an attempt to prepare "foreign intervention".

The U.N. High Commissioner for Refugees (UNHCR) "is competent for (organizing) visits of refugee camps that have been set by the U.N., the Security Council has no competence for that," Lavrov said in Slovenia.

A U.S. journalist missing in war-torn Syria is believed to be held by government intelligence agents at a detention center near Damascus, a spokesman for his family said Friday.

James Foley, a 39-year-old freelancer who has filed reports for GlobalPost, Agence France-Presse and other outlets, has been missing in Syria for nearly six months.

Rebels in Syria fired two rockets at Damascus international airport on Friday, hitting an aircraft and a fuel dump and sparking a massive fire, the official SANA news agency reported.

"One rocket hit a kerosene tank and the other hit a parked commercial aircraft, badly damaging it," the agency said, adding that traffic at the facility was "normal" and the fire had been extinguished.

Tunisia's army Friday pressed its hunt for a jihadist group hiding out in a border region with Algeria, an operation in which 15 security force members have been wounded, the interior ministry said.

"The search operations by the defense forces and the national guard are continuing on Mount Chaambi," ministry spokesman Mohamed Ali Aroui told Agence France Presse.

Clashes in northern Iraq killed nine police on Friday, while a car bomb targeting worshipers near a Sunni mosque north of Baghdad left at least five dead, officials said.

The fighting between police and armed men in west Mosul, including mortar rounds fired at checkpoints, killed nine police and wounded seven, police and a doctor said.

The United States still hopes a conference aimed at creating a nuclear weapons-free zone in the Middle East can take place soon, a high-level U.S. official said Friday, urging regional players to cooperate.

"I think it could be very soon, if the will exists among the regional parties to engage with each other and to respect each others' needs," said Thomas Countryman, U.S. assistant secretary of international security and nonproliferation.