Syria said on Wednesday its military command was still studying a proposal for a holiday ceasefire with rebels - contradicting international mediator Lakhdar Brahimi's earlier announcement that Damascus had agreed to a truce.

The statement threw Brahimi's efforts to arrange a pause in the bloodshed in Syria into even more confusion, as the rebels fighting to topple President Bashar al-Assad have given no indication they would be willing to sign up to it.

A previous ceasefire arrangement in April collapsed within days, with both sides accusing the other of breaking it.

Brahimi, the joint UN-Arab League special envoy, had crisscrossed the Middle East to push the warring factions and their international backers to agree to a truce over Eid al-Adha - a mission that included talks with Assad in Damascus at the weekend.

"After the visit I made to Damascus, there is agreement from the Syrian government for a ceasefire during the Eid," Brahimi told a news conference at the Arab League in Cairo.

Within an hour, Syria's Foreign Ministry said the proposal was still being studied by the armed forces' leadership. "The final position on this issue will be announced tomorrow," a ministry statement said.

The holiday starts on Thursday and lasts three or four days. Brahimi did not specify the precise time period for a truce.

Nor did the initiative include plans for international observers and rebel sources had earlier told Reuters there was little point if it could not be monitored or enforced.

The two sides are now locked in a battle with huge potential ramifications in the northwest.

Syrian warplanes carried out bombing raids on Wednesday on the strategic northern town of Maarat al-Numan and nearby villages while rebels surrounded an army base to its east, an activist monitor said.

Five people from one family, including a child and a woman, were killed in the air strikes, according to Rami Abdelrahman, head of the British-based Syrian Observatory for Human Rights.

Maarat al-Numan has fallen to the rebels, effectively cutting the main north-south highway, a strategic route for Assad to move troops from the capital Damascus to Aleppo, Syria's largest city where the insurgents have taken a foothold.

But without control of the nearby Wadi al-Daif military base, their grip over the road is tenuous. Its capture would be a significant step towards creating a "safe zone" allowing them to focus forces on Assad's strongholds in southern Syria.

The rebels say the ferocity of counter-attacks by government forces shows how important holding the base is to Assad's military strategy.

Opposition activist footage on Wednesday showed a column of grey smoke rising after a bomb hit the village of Deir al-Sharqi, a few kilometres (miles) south of the base.

Meanwhile, hundreds of Syrian refugees have poured into a makeshift refugee camp at Atimah overlooking the Turkish border, fleeing a week of what they said were the most intense army bombardments since the uprising began.

"Some of the bombs were so big they sucked in the air and everything crashes down, even four-storey buildings. We used to have one or two rockets a day, now for the past 10 days it has become constant, we run from one shelter to another. They drop a few bombs and it's like a massacre," one refugee, a 20-year-old named Nabil, told Reuters at the camp.

The army has lost swathes of territory in recent months and relies on air power and heavy artillery to push back the rebels fighting to topple Assad.

More than 32,000 people have been killed in the conflict, which began with peaceful pro-democracy protests in March 2011 before descending into civil war as repression increased.

Human Rights Watch said the Syrian air force had increased its use of cluster bombs across the country in the past two weeks. The New York-based organisation identified, through activist video footage of unexploded bomblets, three types of cluster bombs which had fallen on and around Maarat al-Numan.

Cluster bombs explode in the air, scattering dozens of smaller bomblets over an area the size of a sports field. Most nations have banned their use under a convention that became international law in 2010, but which Syria has not signed.

Russia said on Wednesday the rebels had acquired portable surface-to-air missiles including U.S.-made Stingers - a weapon that would help bring down warplanes and helicopters which have bombed residential areas where rebels are hiding.

Opposition activist footage has shown rebels carrying Soviet-made surface-to-air missiles, but footage of Stingers has yet to appear.

In contrast to the Libya crisis last year, the West has shown little appetite to arm the Syrian rebels, worried that weapons would fall into the hands of Islamic militants.

Russia, which has supported Assad through the conflict, sold his government $1 billion worth of weapons last year and has made clear it would oppose an arms embargo in the UN Security Council.

A total of 190 people were killed across Syria on Tuesday, the Observatory said.-Reuters