Syria conflict: Dozens killed in strikes on Talbiseh
Almost 50 people have been killed by Syrian government air strikes in an opposition-held town, activists say.
Six children were among those who died as Talbiseh, in Homs province, was bombarded for two days, the Syrian Observatory for Human Rights reported.
A dozen rebel fighters were also killed, the UK-based group added.
Meanwhile, at least 15 children have died in another opposition-held area of Syria, reportedly after being given contaminated measles vaccinations.
The main opposition alliance, the National Coalition, has launched an investigation and halted the vaccination programme it was organising in the northern province of Idlib.
The air strikes of Talbiseh reportedly began on Monday and continued into Tuesday. State media said the army had targeted a meeting of "terrorists".
The death toll from the bombardment was expected to rise because bodies were still being pulled out of the rubble and dozens of people, including children, had been critically injured, the Observatory said.
"Residents woke up from the massacre [on Monday] only to witness another terrifying massacre," a local activist group wrote on Facebook.
The post said Talbiseh was "filled with civilians and displaced who cannot find bread to eat, chased by the shelling of regime forces".
Videos purportedly of the aftermath showed a man weeping as he clutched the body of his baby son, as well as people praying over the bodies of a mother and her five children.
Talbiseh is on the country's main north-south motorway about 10km (6 miles) north of the city of Homs, which had been a centre of the uprising against President Bashar al-Assad.
Rebel forces abandoned their last stronghold in the centre of Homs in May after more than a year of siege and bombardment.
The government now controls most of Damascus, along with the motorway from the capital through to Homs and the western Mediterranean coast. Rebels control much of the north and east.
Six people also were killed in a government air raid on the northern city of Aleppo on Wednesday, and another six died when the Damascus suburb of Douma was attacked by jets, the Observatory said.
It is not known what caused the children's deaths in eight opposition-held towns in Idlib province, but parents accused opposition health authorities of not storing the vaccines properly or using out-of-date medication.
A doctor at a clinic in the town of Jarjanaz said the children, some just babies, had exhibited signs of "severe allergic shock" about an hour after they had been given the vaccines, with many suffocating to death as their bodies swelled.
Abdullah Ajaj told the Associated Press that all had the same symptoms to varying degrees, and that it was the first time he had seen them after administering vaccinations.
"There was shouting and screaming, it was hard for the parents. You get your child vaccinated and then you find your child dying, it's very hard."
Opposition officials denied the allegations of negligence, saying the vaccines had come from the United Nations Children's Fund (Unicef) and the World Health Organisation (WHO), via the Turkish government.
They said the same batch had been used successfully to vaccinate 60,000 children in recent days and claimed a preliminary investigation pointed to a "security breach by vandals likely connected to the regime".
A Lebanon-based public health specialist, Fouad Fouad, told AP that an out-of-date vaccine was more or less harmless and "cannot cause death".
The conflict in Syria and the resultant breakdown in state institutions have meant that diseases such as measles and polio have been spreading.
More than 191,000 people have been killed and nine million displaced from their homes since the uprising began in 2011.