Twelve civilians were killed in regime airstrikes in Syria's northwestern de-escalation zones, sources with the White Helmets civil defense agency said yesterday.

The attacks targeted the towns of Maarat Al-Numan and Maarat Herma in Idlib province, the sources said.

Also, regime forces and Iran-back terrorist group shelled the town of Khan Sheykhun and the villages of Al-Kassabiyya, Abdin, Karasaa, Kafr Sajna and Al-Naqeer.

These new deaths brought the figure to more than 455 civilians who have lost their lives in Idlib since April 25.

Idlib is the opposition's last enclave. Its pre-war population of 1.5 million has swelled to around 3 million with new refugee waves after it was designated a "de-escalation zone" under the Astana agreement between Turkey, Russia and Iran in May 2017 to pave the way for a permanent political solution in Syria.

The regime has intensified their attacks on the area since April 26 under the pretext of fighting Hayat Tahrir al-Sham (HTS) militants holed up inside Idlib. The intermittent attacks and bombardment have killed, wounded and displaced thousands of people. Residential areas have been destroyed by indiscriminate attacks while numerous educational facilities, health facilities and residential areas have collapsed or have become unusable after being targeted by bombs.