French president Francois Hollande on Friday called for stiffer sanctions against his Syrian counterpart Bashar al-Assad, and increased support for rebels seeking Assad’s ouster, at a meeting of Western and Arab powers.

More than 16,500 people are estimated to have been killed in the uprising against Assad’s regime. Key Syria allies Russia and China are not attending despite reports of changing attitudes in Moscow.

The Paris meeting follows a gathering in Tunis and another in Istanbul, both of which called in vain for tougher action against Assad’s government. 

“Bashar al-Assad must go,” Hollande told a meeting of foreign ministers and senior diplomats from the “Friends of Syria” group, who met in Paris to discuss an end to the bloody 16-month-old crisis. 

“It’s in the interest of Syria, of its neighbors and everybody who wants peace in the region,” Hollande added.

“The Syrian regime believes violence is the solution … It is essential that Assad leaves power and an oppositional body be installed.”

Hollande said he wanted the participants at the talks – who were cheered by reports of the defection of a senior Syrian general – to also agree to step up humanitarian aid to the country.

The French president also urged the more than 100 countries attending to reject “impunity for crimes,” to push “the real and effective application of economic sanctions,” greater backing for the opposition – including “giving them means of communication,” humanitarian aid and a pledge to “rebuild this beautiful country.”

Meanwhile, Abdulbaset Seyda, the head of the Syrian National Council, asked for the implementation of United Nations special envoy Kofi Annan’s peace plan under Chapter 7 of the UN charter, which allows for sanctions ranging from economic measures to an arms embargo, and if necessary military force.

Seyda also called for humanitarian corridors and a no-fly zone.

Chapter 7 was last used against Libya last year. But doing so against Syria at the UN Security Council is highly unlikely, given Russia and China’s use of their veto powers to protect Assad thus far.

Speaking as US Secretary of State Hillary Clinton flew to Paris for the meeting, one official said it was time “to put this all together under a Security Council resolution that increases the pressure on Assad, including having real consequences” such as economic sanctions.

“We, and we believe most of the countries represented in Paris, think that has to include Chapter 7 economic sanctions on Assad,” the official said aboard Clinton’s plane and asking to remain anonymous.

“Many of the countries in Paris already have those sanctions but globalising them will be very important. That is the argument that we will continue to make to Russia and China.”

“There’s already a lot of work being done in New York in terms of thinking through what this resolution might look like,” said another US official.