Updated

Russia's foreign minister insisted Wednesday that only the United Nations can assess how well international envoy Kofi Annan's cease-fire plan is being implemented in Syria, ruling out other groups with an interest in the outcome.

Sergey Lavrov specifically mentioned the Friends of Syria as a group that should have no say in the evaluation. The group includes more than 60 countries, including the U.S., European and Middle East nations that have been highly critical of Syrian President Bashar Assad and his regime.

Syrian forces have continued shelling opposition strongholds despite a pledge by Assad's government to respect a week-old cease-fire and withdraw troops from urban centers in line with Annan's plan, raising fears that the truce will fail.

Syria is a key Middle East ally for Moscow, and Russia — along with China — has twice shielded Syria from U.N. sanctions over its yearlong, deadly crackdown on a popular uprising. But Moscow has strongly supported the Annan plan, which aims to end the violence that is estimated to have killed more than 9,000 people so far.

Lavrov accused Syrian opposition forces of provoking the government's backlash in order to thwart the cease-fire. He urged all nations that have leverage with the opposition to force it to abide by cease-fire.

"There must be a tough demand not to allow any provocations and respect the cease-fire," Lavrov told a news conference following talks with his Moroccan counterpart.

"We are worried by continuing attempts to 'privatize' Annan's plan and empower self-proclaimed structures such as the Friends of Syria with assessing its fulfillment," he added.

Lavrov also urged U.N. Secretary General Ban Ki-moon to speed up the deployment of a full-fledged observer mission in Syria.

Also Wednesday, the French Foreign Ministry firmed up its guest list of top diplomats for an urgent Paris meeting about the Syria situation as part of the Friends of Syria effort.

Ministry spokesman Bernard Valero said 14 delegations were expected, including U.S. Secretary of State Hillary Clinton and the foreign ministers of Germany, Qatar, Jordan, Morocco and Saudi Arabia.

Asked whether envoys from Russia and China had been invited, Valero said: "This is not a substitute to the work of the (U.N.) Security Council and so it wouldn't be appropriate to invite council members ... This is a complementary process in support of its action."