Turkish warplanes struck pro-Syrian government forces in the northwestern Afrin region of Syria on Saturday, killing at least 36 of them, as Turkey's assault in the Kurdish region gathered pace, the Syrian Observatory for Human Rights said.
The pro-Syrian government forces entered Afrin last week in support of the Kurdish YPG militia, the stated target of the operation launched by Turkey and allied Syrian rebel fighters in January.
The Observatory said the air strike, which hit a camp in Kafr Jina, marked the third time in 48 hours that Turkish warplanes had struck pro-government forces in Afrin.
The Syrian Democratic Forces (SDF), a YPG-led militia alliance, said in a statement that Turkish air strikes had targeted positions held by the Syrian army's "popular forces" from 5 a.m. (0300 GMT) until 10 a.m. (0800 GMT).
It did not say where or give a death toll.
Turkish Prime Minister Binali Yildirim said his country's forces had captured the town of Rajo from militants. The Observatory said the Turkish army was in control of about 70 percent of the town, about 25 km (16 miles) northwest of Afrin city.
The SDF statement said a group of Turkish forces and allied Syrian factions had infiltrated Rajo, where it said clashes were continuing between SDF forces and the attackers.
Turkey views the YPG as an extension of the Kurdistan Workers' Party (PKK), which has fought a three-decade insurgency in Turkey and is deemed a terrorist group by the United States, the European Union and Turkey. The YPG has been an important ally for the United States in the fight against Islamic State.