Unidentified airstrikes have killed 12 civilians in an opposition-held pocket in Syria's southern province of Daraa, AFP reported Wednesday (July 18th).

The deadly strikes hit Nawa, the last town under opposition control in Daraa, late Tuesday, the Syrian Observatory for Human Rights said.

The Observatory said it could not determine whether the strikes on the town in the west of the province were carried out by the regime or its Russian ally.

The regime has in less than a month retaken more than 90% of Daraa province. But opposition fighters in Nawa have resisted.

After regime forces launched an offensive on June 19th, Russia pressured opposition fighters to hand over eastern parts of the province in early July, and the provincial capital last week.

Other towns in the west of the province have also joined the deal.

"Negotiations were ongoing Wednesday towards Nawa joining the reconciliation deal" with the regime, Observatory head Rami Abdel Rahman said.

A ceasefire deal announced earlier this month in Daraa did not include extremists.

On Wednesday, Russian airstrikes and regime barrel bombs targeted hills outside Nawa held by Tahrir al-Sham.

Heavy airstrikes also pounded a southwestern corner of the province controlled by the "Islamic State of Iraq and Syria" (ISIS).