"Regime warplanes conducted raids on Rastan, Talbisseh, and Zaafarani in Homs province," said Rami Abdel Rahman, head of the Syrian Observatory for Human Rights.
He said five people had been killed in Zaafarani, seven in Rastan, and 15 in Talbisseh.
"The number of dead may rise because there are dozens of wounded, some of whom are in critical condition, and others who are still under the rubble," the Observatory reported.
The three locations, which lie next to each other in Syria's central Homs province, are controlled by various rebel, Islamist and jihadist groups including Al-Qaeda's Syria affiliate Al-Nusra Front.
Today, fierce clashes between regime forces and IS jihadists raged in the Shaer gas field, the largest in Homs province.
IS has tried for months to seize the gas field, one of the last still in regime hands.