China said Wednesday Syria's foreign minister had pledged to respect U.N. envoy Kofi Annan's peace plan and cooperate with a U.N. team sent to monitor a fragile ceasefire in the restive state.

"Syrian Foreign Minister Walid Muallem... said Syria would continue to... respect and implement Annan's 'six-point proposal'," China's foreign ministry quoted Muallem as telling his Chinese counterpart Yang Jiechi in Beijing.

U.S. Secretary of State Hillary Clinton is set to attend talks in Paris on Thursday as part of international efforts to end the violence in Syria, a U.S. official said Wednesday.

"We're now expecting this meeting will happen and she will be there," a senior State Department official told reporters traveling with Clinton from Brasilia to Brussels.

Syria is holding up an accord with an advance party of U.N. ceasefire monitors which threatens approval for the full mission, diplomats said Tuesday.

Negotiations have become deadlocked on a memorandum of understanding which would allow the eight U.N. monitors currently in Syria to operate across the country, diplomats said.

Iran's intelligence ministry says it is holding more than 15 Iranian and foreign suspects belonging to an Israeli-linked "assassination" network, according to media reports on Tuesday.

It also said it had uncovered a spy base run by Israel's Mossad in an unspecified neighboring country.

The United States said Tuesday that persistent violence in Syria was "unacceptable" and demanded that President Bashar al-Assad do more to comply with a peace plan to end months of bloodshed.

State Department spokesman Mark Toner said that a ceasefire -- which went into force on Thursday -- was eroding due to the daily violence and said that the opposition was upholding its side of the peace deal.

U.N. observers acknowledged on Tuesday that they face a tough task to firm up a ceasefire in Syria, as more civilians were killed in the latest violence on the sixth day of a tenuous truce.

The Syrian Observatory for Human Rights said security forces killed five civilians, while the Local Coordination Committees, the main activist group spurring protests on the ground, said 66 civilians were killed across the country.

Libyan authorities have met resistance in talks for the handover of Seif al-Islam, the son of slain leader Moammar Gadhafi, who is still being held in Zintan, a negotiator told Agence France Presse on Tuesday.

Zintan officials told representatives of the ruling National Transitional Council that people in the town "want Seif to be tried locally because the (interim) government is weak," an NTC member said on condition of anonymity.

Qatari Prime Minister Sheikh Hamad bin Jassem al-Thani said Tuesday that no progress has been made to end Syria's deadly 13-month crisis.

"We hope the Syrian government responds" to U.N.-Arab League envoy Kofi Annan's six-point peace plan, Sheikh Hamad told an Arab ministerial meeting in Doha. "We don't see any progress in implementing" it.

Israeli Prime Minister Benjamin Netanyahu on Tuesday received a letter from president Mahmoud Abbas about the moribund peace process, as he met in Jerusalem with two Palestinian officials, his office said.

The brief meeting was described by the Palestinians as "serious," with both sides saying Netanyahu would reply with his own letter to Abbas "within two weeks."

A group of 50 countries supporting sanctions against Bashar al-Assad's Syrian regime on Tuesday issued a statement denouncing continued arms sales to Damascus.

After meeting in Paris, the countries expressed "strong disapproval of any financial or other support, in particular the continuation of arms sales to the Syrian regime", in a clear reference to Russia.