* Haffeh full of empty homes and burned-out buildings
* China snubs French proposal to let UN enforce Annan plan
* Plan for international Contact Group to meet on June 30
By Khaled al-Hariri
HAFFEH, Syria, June 14 (Reuters) - A United Nations convoy arrived in the Syrian town of Haffeh on Thursday to find it almost deserted, with state buildings burnt down, shops abandoned and a body lying in the street.
U.N. monitors, who have been trying to enter the town after several days of intense clashes between forces loyal to President Bashar al-Assad and rebel fighters, were forced to turn back on Tuesday when a mob attacked them.
Rebels pulled out of the town this week, but joined the United States in warning that some of the thousands of remaining citizens could be killed in cold blood.
A Reuters photographer saw smoke rising from destroyed buildings and burnt-out cars in Haffeh, where there were signs of heavy bombardment. Only a handful of residents were in evidence, and one said 26,000 people had fled.
The main offices of the ruling Baath party, the town's post office and a branch of the Ministry of Agriculture had also been burnt down. A body lay abandoned on the pavement and abandoned shops stood open with boxes of vegetables still out in front.
The uprising against Assad's autocratic rule began as a peaceful pro-democracy movement in March 2011 but has increasingly given way, after a bloody crackdown by Assad's forces, to an armed insurgency.
The United Nations says more than 10,000 people have been killed by government forces, while Syria says some 2,600 members of the security forces have been killed by foreign-backed "Islamist terrorists".
With a ceasefire brokered by international mediator Kofi Annan failing to take hold, world powers are divided over the next move.
Russia and China, both permanent members of the U.N. Security Council with veto power, have blocked efforts by Western powers to condemn Assad or call for his removal.
Diplomats said major powers were working towards holding a crisis meeting on Syria in Geneva on June 30 to try to get the plan back on track.
IRAN THE STICKING POINT
Annan, the United Nations-Arab League mediator, has called for a "Contact Group" to convened as soon as possible, but the United States is opposed to the involvement of Iran, Syria's main ally in the region.
"It is not confirmed but people are still working toward something on the 30th," a diplomat told Reuters. "We're moving toward the 30th but nothing is confirmed," said another. But a third said Iran's participation was still a sticking point.
Annan's spokesman Ahmad Fawzi said this week that if the Contact Group held a meeting, it would aim to "give teeth" to the Annan plan, not to create a new one.
He said Annan was in "urgent and intensive consultations with member states in order to reach consensus on the shape and formula of the Contact Group meeting".
U.S. Secretary of State Hillary Clinton said this week that Washington had information that Russia was in the process of supplying Syria with helicopters - which have been used in government assaults on towns and cities.
Syria's ambassador to Moscow told Reuters on Thursday that Russia was "not delivering any helicopters to Syria".
Meanwhile, violence raged across Syria.
The army fired heavy artillery on the eastern city of Deir al-Zor, killing at least 11 people, after a ground offensive met heavy resistance, opposition sources said.
The overnight barrage from nearby hills followed the withdrawal of hundreds of troops backed by tanks that had entered the city on Wednesday to root out rebels, the sources said. About 200 people were wounded in the shelling, they said.
In southern Damascus, a car bomb exploded in a car park near the gold-domed Shi'ite shrine of Sayyida Zeinab, wounding two people, activists and state media said.
The blast gouged a deep crater in the tarmac, wrecked several buses and smashed car windows across a wide area, the state news agency SANA reported.
(Additional reporting by Dominic Evans in Beirut, Khaled Yacoub Oweis in Amman, Chris Buckley in Beijing, Nastassia Astrasheuskaya and Thomas Grove in Moscow, Stephanie Nebehay in Geneva; Writing by Oliver Holmes; Editing by Kevin Liffey)