Syria is showing "contempt" towards the U.N. atomic watchdog by refusing to cooperate over a suspected undeclared reactor destroyed by Israel in 2007, the U.S. envoy to the agency said Friday.

President Bashar Assad's government "is using its brutal repression of the Syrian people as an excuse for not cooperating with the agency's investigation," Robert Wood told a meeting of the International Atomic Energy Agency's board.

A Syrian opposition chief will visit China from Sunday to hold talks on an end to the violence in the war-torn nation and a Syrian-led political transition, Beijing said.

Hassan Abdel Azim, general coordinator for the Syrian National Coordination Body for Democratic Change (NCC), will visit from September 16 to 20 and will meet Foreign Ministry officials, ministry spokesman Hong Lei said Friday.

Turkish Prime Minister Recep Tayyip Erdogan said Friday the regime of Syrian President Bashar Assad was nearing its "inevitable" end despite violence threatening the entire region.

"Assad's regime is approaching its inevitable end," Erdogan said in comments translated into Russian at a conference in the Ukrainian Black Sea resort of Yalta.

Regime forces used fighter jets and helicopter gunships to pound the city and province of Aleppo on Friday, a day after violence killed at least 125 people across Syria, a watchdog said.

The fighter jets bombarded the rebel-held towns of Al-Bab and Marea near Aleppo city, while fierce battles raged around the military airport at Minnigh, also in Aleppo province, said the Syrian Observatory for Human Rights.

Pope Benedict XVI arrived on Friday for a three-day visit to Lebanon, to bring a message of peace for the Middle East.

His plane arrived at Beirut international airport to a massive official, media, and popular reception.

The U.S. Department of the Treasury imposed on Thursday sanctions against Hizbullah's leadership in Lebanon, further exposing Hizbullah's active support to the regime of Syrian President Bashar Assad, as well as its role in terrorist activities.

“Hassan Nasrallah, Hizbullah's secretary general, is being designated today pursuant to Executive Order (E.O.) 13582, for providing support to the Syrian government,” said the Treasury in a statement.

French Defense Minister Jean-Yves Le Drian lauded on Thursday the Lebanese government's decision to disassociate itself from the Syrian crisis, saying that France will continue to support Lebanon.

He said: “France will maintain its support for the Lebanese army through all possible means.”

Peace envoy Lakhdar Brahimi said on Thursday the deadly conflict in Syria was getting worse as he arrived on his first official trip aimed at ending nearly 18 months of violence.

"We came to Syria to hold meetings with our Syrian brothers because there is a big crisis, and I think it is getting worse," the official SANA news agency quoted the U.N. and Arab League envoy as saying on arrival at Damascus airport.

Lebanese Forces Samir Geagea noted on Thursday that major revolutions cause pain to all those involved, especially Christians because they are smaller in numbers than the rest of the population in the Arab world.

He said in an interview to the BBC: “The Arab Spring will however produce open-minded societies that will provide better development for the Christians.”

Al-Mustaqbal parliamentary bloc leader Fouad al-Saniora urged the Lebanese people to unite against continuous Israeli violations of Lebanon's sovereignty, which is now being violated by Syria, welcoming the visit of Pope Benedict XVI to Lebanon.

“The souls of our citizens are being violated by Israel and today by the Syrian regime,” Saniora told reporters after meeting with Maronite Patriarch Beshara al-Rahi in Bkirki.