The Chaldean Catholic bishop of Aleppo, Antoine Audo, said on Thursday that up to 30,000 Christians have fled the Syrian city and spoke of his concern about two priests kidnapped weeks ago.

Audo, who was in Rome as a representative of the Caritas-Syria charity for a meeting of regional humanitarian organizations, told Agence France Presse that the situation in the war-ravaged city was "painful".

A suicide bomb attack on a mosque in central Damascus on Thursday killed 42 people, including a prominent pro-regime Sunni cleric and his grandson, and wounded 84 others, Syria's health ministry said as the opposition's chief condemned the bombing as a "crime".

"The number of those martyred in the terrorist suicide attack in the Iman Mosque rises to 42 martyrs with 84 injured," a bulletin on state television said, citing the ministry.

European Union foreign policy chief Catherine Ashton on Thursday strongly condemned “the attacks on targets on Lebanese soil by the Syrian armed forces,” noting that “these actions constitute a violation of Lebanon's sovereignty.”

She stressed that “attacks against any of the neighboring countries are unacceptable.”

Syrian actress Ragda sparked a melee in a Cairo poetry convention after she praised Syria's President Bashar Assad, angering an Islamist in the crowd, witnesses said.

The actress, who lives in Cairo, read a poem praising the dictator and condemning the Muslim Brotherhood, the ruling movement in Egypt whose Syrian branch opposes Assad, during the convention on Wednesday.

Foreign Minister Adnan Mansour criticized on Thursday reports that said he had deemed Syrian shelling of Lebanese territory as rumors, saying that he will not comment on the campaign being directed against him.

He told the National News Agency: “I abide by the orders of President Michel Suleiman, the prime minister, and government.”

Syrian rebels have gained ground in the Golan Heights, which is partly occupied by Israel, launching coordinated attacks in the area and in nearby Daraa province, a watchdog said on Thursday.

"It appears that the rebels launched coordinated attacks on multiple parts of the Golan, taking control of areas and villages in the province of Quneitra," Syrian Observatory for Human Rights director Rami Abdel Rahman told Agence France Presse.

The United Nations will launch an independent investigation into a Syrian government allegation that opposition rebels staged a chemical weapons this week, U.N. leader Ban Ki-Moon said Thursday.

"I intend for this investigation to start as soon as practically possible," Ban told reporters.

Syrian opposition leader Soheir Atassi of the Syrian National Coalition grouping said on Thursday she was rejoining the body a day after abruptly "freezing" her membership.

"The main reason I froze my participation is the failure of organizational work and the lack of professionalism," Atassi wrote on her Facebook page.

President Bashar Assad called the more than two-year deadly conflict in Syria a "battle of will and resistance," in remarks published in newspapers on Thursday.

"Today, all of Syria has been wounded," he was reported as saying on a visit the previous day to an educational center in the capital.

Syria released on Thursday a Lebanese Salafist who had been seized in an ambush by Syrian regime troops in the town of Tall Kalakh near the border with Lebanon last year.

Hassan Srour was handed to Lebanon's General Security, which said in a communique that his release came as a result of contacts between the department's chief Maj. Gen. Abbas Ibrahim and Syrian authorities