UN humanitarian affairs chief Stephen O'Brien said on Friday that he was "horrified and sickened" by the attacks that targeted camps of internally displaced Syrians in Idlib province near Syria's border with Turkey.

The British-based Syrian Observatory for Human Rights, first reported on the attacks on Thursday, after airstrikes targeted a camp in Sarmada. The town lies in rebel-held territory in Syria's northwestern Idlib province, about 40 kilometers (25 miles) west of divided Aleppo. At least seven children, were among the 30 victims, the watchdog said.

The refugees targeted in the strikes had reportedly been sheltering from fighting in Syria's northern hub of Aleppo and Palmyra, the heritage city recaptured by Syrian government forces with Russian air support.

"If this obscene attack is found to be a deliberate targeting of a civilian structure, it could amount to a war crime," O'Brien said.

It was not immediately who was responsible for the strikes, although some unconfirmed reports said they belonged to regime forces.

"We've seen early claims that this was regime strike, but we just want to be absolutely sure before we level blame at somebody," US State Department Mark Toner said in Washington. "But it's totally in keeping with the types of ... airstrikes that regime has carried out ... against innocent civilians."

Truce in Aleppo

A temporary ceasefire in the northern city of Aleppo was also reportedly breached on Friday after insurgent groups captured a strategically important village from Syrian government forces.

The al Qaeda-linked al Nusra Front and allied Islamists seized Khan Tuman and surrounding villages after less than 24 hours of clashes, killing at least 70 people, the Syrian Observatory for Human Rights said.

Syria's central province of Homs was also targeted in a twin bombing on Thursday in the village of Mukharam al-Fawkani. According to Syria state media and the regional governor, Talal Barrazi, at least 10 people were killed, including four children.

Similar deadly attacks in the Homs area in the past have been claimed by the "Islamic State" (IS) militant group, which earlier this week overran an adjacent gas field.

ksb/msh (AP, Reuters, dpa)