BEIRUT  - Helicopter gunships on Monday fired on rebels in central and northwestern Syria in a bid to snuff out armed opposition as violence killed 74 people across the country, a watchdog said.

The rebel positions were targeted from the air in Al-Heffa, in the northwestern province of Latakia, and in Rastan, in the central region of Homs, said the Syrian Observatory for Human Rights.
Government troops have been pounding Al-Heffa daily for the past week to crush fighters of the Free Syrian Army deployed in the rugged countryside near the Turkish border, activists said. Activists said Monday's assault was violent and described the situation in Al-Heffa as "terrible," although there were no immediate reports of any casualties.
"Army tanks are deployed at the entrances of the town. They have never come this close before," activist Sema Nassar told AFP in Beirut via Skype, weeping as she spoke. "There's only one doctor working to treat the wounded in the town," of 30,000 people, said Nassar, adding most of the residents have fled.
Regime forces also used helicopters to attack rebel positions in Rastan, a town which has faced intermittent army shelling "for months," the Britain-based Observatory said.
Four civilians, including a young girl, were killed in the violence, it added.
Troops have trying to overrun Rastan since mid-May, after rebel fighters from the battered city of Homs regrouped in the town which straddles the main highway linking Damascus to the north.
In restive Qusayr, also in Homs province, another two civilians were killed, the Observatory said. Activists in the central province of Hama told AFP that regime troops continued to target towns and villages in the region, where anti-regime sentiment was strong.
At least five people were killed across Hama on Monday, the Observatory said. Elsewhere, at least nine people were killed in the eastern province of Deir Ezzor, where rebels and regime forces clashed, while a blast in the northwestern city of Idlib killed a civilian and seven regime forces. More than 14,100 people have been killed since an anti-regime revolt broke out in March last year, including 9,862 civilians, 3,470 soldiers and 783 army defectors, according to the watchdog.
Meanwhile, UN-Arab League envoy Kofi Annan said he is gravely concerned by increased fighting between Syria's troops and rebel forces as violence on Monday killed dozens of people across the country.
Annan "is gravely concerned by the latest reports of violence coming out of Syria and the escalation of fighting by both government and opposition forces," his spokesman Ahmad Fawzi said.
Fawzi said Annan, who brokered a faltering plan aimed at ending 15 months of bloodshed in Syria, cited shelling in Homs and the reported use of mortars, helicopters and tanks in Al-Heffa, a beleaguered town in the northwest. "There are indications that a large number of civilians are trapped in these towns," said Fawzi.
"The Joint Special Envoy demands that the parties take all steps to ensure that civilians are not harmed, and further demands that entry of the UN Military Observers be allowed to the town of Al-Heffa immediately." Russian Foreign Minister Sergei Lavrov will visit Iran on Wednesday to discuss upcoming talks in Moscow on the Syria crisis, as well as Tehran's nuclear programme, his office said.
Moscow has proposed holding an international conference on Syria aimed at saving Annan's tattered plan and has pressed for Iran's inclusion despite strong reservations from Britain, France and the United States. "Without Iran's involvement, the opportunity to exert constructive pressure on Syria will not be implemented in full," its foreign ministry said.
France said it would hold talks with Russia on its idea of an international Syria conference, as it urged the new head of the Syrian National Council to unite the opposition.
The rebel Free Syrian Army, meanwhile, has called for a campaign of civil disobedience and urged officers and troops in Assad's military to jump ship and join the opposition ranks.
Colonel Kassem Saadeddine, spokesman for the opposition fighters in Syria, urged officers and men in Syria's regular army "whose hands are not tainted with blood to join the fighters."
Meanwhile, the United States on Monday voiced concern that Syria's government is planning a new massacre after accounts that tanks have approached the edge of the city of Al-Heffa.
"The US joins Kofi Annan in expressing deep alarm by reports from inside Syria that the regime may be organizing another massacre," State Department spokeswoman Victoria Nuland told reporters.