Syria's army blasted rebel strongholds in Damascus with mortars Sunday, sparking the "most intense" fighting in the capital since the revolt erupted 16 months ago, a monitoring group said.

The army's offensive, aimed at driving rebels of the Free Syrian Army (FSA) out of Damascus, was launched soon after Syria's foreign ministry held a press conference to deny its troops had carried out a massacre in Treimsa village.

U.N. leader Ban Ki-moon on Saturday appealed to China's foreign minister to use his "influence" to help bring pressure on Syria's President Bashar Assad to end conflict, a U.N. spokesman said.

China is a key player in a U.N. Security Council dispute over sanctions against the Syrian leader. It has backed Russia in rejecting western demands for international action to press Assad.

The United Nations may have to curtail humanitarian operations in Syria unless new funds are raised at a key donors' meeting on Monday, officials warned.

U.N. agencies will this month step up their food aid to reach 850,000 people in the conflict-stricken country even though it has only received promises for one fifth of a $189 million appeal.

Turkish Prime Minister Recep Tayyip Erdogan on Saturday branded the massacre of 150 people in a central Syrian village as "attempted genocide" and said the regime was doomed.

"There is nothing more to be said about Syria," he said, speaking of the bloodshed in the village of Treimsa in Hama province, which activists said was bombarded by government forces.

French Ambassador to Lebanon Patrice Paoli hailed on Saturday the Lebanese democracy and coexistence, which became a model in the region.

“Lebanon’s democracy, freedom and coexistence among its citizens became a model in the region, in addition to the stability it witnessed during the recent months,” Paoli said in a ceremony held in Kasr al-Sanawbar on the occasion of French Bastille Day.

Interior Minister Marwan Charbel delegated anew a security official to Turkey to address the case of the abducted Lebanese pilgrims in Syria, the Central News Agency reported on Saturday.

According to the news agency, the kidnappers expressed readiness to free six out of the eleven Lebanese pilgrims until investigations with the rest are complete.

Nawaf Fares, who this week defected as Syria's ambassador to Iraq, on Saturday accused President Bashar Assad of allowing al-Qaida to use Syria as a springboard for attacks in his former host country.

Fares, the latest high-level official to abandon Assad, in an interview on Al-Jazeera television also accused Iraqi Prime Minister Nouri al-Maliki of taking a stance toward Syria that was "contradictory" to the truth.

U.N. observers in Syria visited on Saturday the central village of Treimsa, where more than 150 people were killed this week, according to a spokeswoman for the U.N. mission and an activist on the ground.

An activist in Hama province calling himself Abu Ghazi said the observers had met residents of the village and "inspected places that were bombed and where there were traces of blood."

Iraq's prime minister on Saturday condemned the killing of more than 150 people in a central Syrian town two days ago, describing the deaths as an "ugly massacre."

"The ugly massacre that took place in Treimsa town, in Hama province, provokes feelings of concern and condemnation," Nouri al-Maliki said in a statement published on his official website.

Syrian troops and pro-regime militias stormed and torched a southern town on Saturday, reports said, as U.N. observers visited a central village where a mass killing has provoked harsh global condemnation.

Hundreds of soldiers backed by helicopter gunships attacked Khirbet Ghazaleh in the province of Daraa -- the cradle of a 16-month uprising -- amid heavy gunfire, the Syrian Observatory for Human Rights said.