France will ask for an urgent UN Security Council ministerial meeting on Syria to try to end the diplomatic deadlock and prevent further bloodshed, Foreign Minister Laurent Fabius said on Monday.
President Bashar Assad's forces attacked rebel fighters in the city of Aleppo during the weekend, drawing condemnation from Western powers, who say the authorities in Syria have lost all legitimacy.
Branding Assad an "executioner," Fabius said the country was headed for a massacre, and urged the United Nations to do everything it can to stop the crisis.
"We're going to ask for a meeting of the Security Council, probably at the ministerial level, before the end of this week," he told RTL radio.
Western powers have thus far been unsuccessful in ending an impasse at the UN over the Syrian crisis, with Russia and China blocking efforts to put more pressure on Assad.
France is due to take over the presidency of the United Nations Security Council on Wednesday, and President Francois Hollande has said he will try to convince Russia and China to support further sanctions.
The United Nations expressed concern for hundreds of thousands of civilians, who have fled Syria's largest city Aleppo, amid intensifying clashes between government and rebel forces.
An estimated 200,000 of the city's 2 million have fled, the UN's Emergency Relief Coordinator Valerie Amos said late Sunday in New York, citing figures from the Red Cross and Red Crescent Societies.
"I am extremely concerned by the impact of shelling and use of tanks and other heavy weapons on people in Aleppo," she said.
"I call on all parties to the fighting to ensure that they do not target civilians and that they allow humanitarian organizations safe access to bring urgent and life-saving help to people caught up in the fighting."
Government troops intensified their attacks to regain control of areas of the city held by rebels seeking to topple the regime of President Bashar Assad.
Helicopter gunships fired on the south-eastern district of Salaheddine, according to the opposition Syrian Observatory for Human Rights.
The rebels said they had blocked the army from entering several districts in Aleppo and destroyed tanks. Their claims could not be independently verified.
At least 95 people were killed Sunday in Syria, mainly in Aleppo and in suburban areas of Damascus and Daraa in the south, said the opposition.
The opposition National Syrian Council planned talks in Cairo on Tuesday to discuss forming a transitional government, member Khaled Khuga told DPA.
Western powers have recently called on position groups to patch up their differences and formulate a united vision for post- Assad Syria.
The weekend's clashes were the heaviest of the uprising, which has claimed more than 20,000 lives since it began in March 2011, according to the Syrian Observatory for Human Rights.
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