Gunmen have killed two army colonels in the heart of Syria’s largest city and a stronghold of support for President Bashar Assad.
State media blamed terrorists.
Separately, in the central province of Hama, rebels attacked an army truck and killed two soldiers, activists said. Fresh clashes also broke out between government troops and army defectors in the country’s north and south.
at least three civilians were killed in army raids on rebellious villages in the Idlib province along Syria’s northern border with Turkey.
The violence came as Arab leaders meeting at a Baghdad summit struggled with deep divisions about how to address Syria’s crisis.
The leaders are expected to pass a resolution calling for a ceasefire and an immediate, daily two-hour stop to fighting across Syria to permit aid to suffering civilians.
Such a resolution would fall short of previous calls by the body that Assad give up power, but would back efforts by UN-Arab League envoy Kofi Annan to broker a political solution.
Syria’s state news agency said four gunmen belonging to an “armed terrorist group” opened fire on the two colonels at a roundabout in the centre of Aleppo, the country’s largest city.
No one immediately claimed responsibility for the attack.
The anti-Assad uprising has become increasingly militarised since it started last March, but Aleppo has largely been spared clashes between government forces and rebels.
However, two mysterious bombings in the city this month killed 29 people. No group claimed responsibility for the attacks.
The UN says more than 9,000 people have been killed since Syrians first took to the street last year to call for political reforms. Assad’s security forces deployed tanks, snipers and pro-regime thugs to quash dissent, and the protests spread. Many in the opposition have also taken up arms to defend their communities and attack government troops.
A flurry of international diplomacy has failed to stop the violence.
The US, Europe and many Arab countries have called on Assad to leave power, and the UN and the Arab League have appointed Annan, a former UN chief, to try to broker a solution.