A ground-to-ground missile was fired on a town in northern Syria at dawn on Sunday and killed at least four civilians, two of them children, a watchdog reported.
Anti-regime activists of the Aleppo Media Centre said the missile, which slammed into a residential area of Tal Rifaat, was a Scud, although this could not be independently verified.
The attack also killed two women, wounded several other people and destroyed many homes in the town in Aleppo province, the Britain-based Observatory said.
The Syrian Revolution General Commission activist network reported 30 wounded and 10 houses destroyed, adding a mother and her two daughters were among the dead.
"The toll could rise, with bodies buried under the rubble," said the Observatory, which relies on a network of sources on the ground for its information.
Amateur video footage posted online by activists showed men clearing away debris in the dark and then removing the body of a child, as cries can be heard from the crowd.
In February, the Observatory cited activists as saying the army fired Scuds on Aleppo city, killing 58 people including 36 children.
Damascus has denied using Scuds.
Elsewhere in Aleppo province, fierce clashes raged inside the Kwiyres military airport, as rebels tried to seize the facility.
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Since the beginning of the year, rebel forces have been fighting what they call the "battle of the airports in Aleppo" to deprive the regime of a key supply route.
Rebels have set their sights on the Aleppo international airport, along with the Jarrah, Kwiyres, Minnigh and Nayrab military fields. They took the Jarrah military airport on February 12.
Meanwhile, in Idlib province, the Observatory reported clashes around the major Abu al-Dhur military airport, which rebels have laid siege to for about a month.
"The rebels have broken into the airport but they are still on the periphery and are engaged in violent clashes with soldiers," Observatory director Rami Abdel Rahman told AFP.
"It's an important military airport because it's still functional," he added.
The Observatory reported clashes in Barzeh, a district of northern Damascus that has seen days of fighting, as well as in the town of Daraya, south of the capital.
The rebel opposition council in the town said government forces have been trying to take Daraya for 167 days.
They reported air raids and artillery fire, saying there was a shortage of medicines due to the "siege" imposed by regime forces.
On Saturday, at least 161 people were killed throughout the country, said the Observatory.