The United States is set to call for tough new U.N. sanctions against President Bashar Assad and his regime figures, as over 100 Western and Arab nations meet Friday in Paris for "Friends of Syria" talks.

The United States is set to call for tough new U.N. sanctions against President Bashar Assad and his regime figures, as over 100 Western and Arab nations meet Friday in Paris for "Friends of Syria" talks.

However, key Syria allies Russia and China -- which both hold U.N. veto rights -- are not attending, which belies the claims 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.

China did not attend either of those meetings, in which the United States, France, Britain, Germany and Arab nations Saudi Arabia and Qatar led a group of more than 60 members, including most EU states and many Arab League nations.

The United States will lead calls at the Paris talks for a tough new U.N. sanctions regime to be imposed on Assad, Washington officials said Thursday.

Speaking as U.S. Secretary of State Hillary Clinton flew to Paris for the Friends of Syria 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 believe most of the countries represented in Paris, and think that has to include Chapter 7 economic sanctions on Assad," the official said aboard Clinton's plane and asking to remain anonymous, referring to a clause within the U.N. charter.

The chapter 7 of the U.N. charter, which allows for sanctions ranging from economic measures to an arms embargo - and if necessary military force - was last used against Libya last year. But it could be highly controversial at the U.N. Security Council, given Russia and China's veto powers.

Paris talks will include a condemnation of the repression and an announcement of "concrete measures" to put pressure on the regime and to support the people and the opposition, a Western diplomatic source told Agence France Presse.

China backed Russia at talks in Geneva last weekend, insisting that Syrians must decide how the transition should occur, rather than allowing others to dictate their fate, and did not rule out Assad remaining in power.

The West insists that Assad should not be part of any new unity government and the Syrian opposition rejected the Geneva talks as making concessions to Damascus under pressure from Russia.