A senior UN adviser on Friday voiced concern over the ongoing violence in northwestern Syria, decrying a distressing rise.

Axar.az reports citing foreign media.

"An alarming intensification of daily violence continues in northwestern Syria. At least 350 civilians are reported to have been killed in recent hostilities in the Idlib de-escalation area," Najat Rochdi, senior humanitarian adviser to the UN special envoy for Syria, said in a statement.

Although Turkey and Russia have agreed to stop acts of aggression and turn Idlib into a de-escalation zone, the Syrian regime has consistently violated the cease-fire, launching frequent attacks inside the de-escalation zone.

Rochdi said some 3 million civilians lack protection and face a deteriorating humanitarian situation and more than 330,000 people have been displaced.

She added that attacks continue on civilian infrastructure, including healthcare facilities.

"Strikes against civilians and civilian infrastructure – including de-conflicted health facilities and humanitarian workers – are absolutely unacceptable and may amount to war crimes," Rochdi added.

The adviser called on the member states to support the UN’s immediate humanitarian priorities, adding that "humanitarian needs are vast across Syria, an estimated 11.7 million people need assistance, 5 million of whom are in acute need."

Syria has been locked in a vicious civil war since early 2011, when the Bashar al-Assad regime cracked down on pro-democracy protests with unexpected ferocity.

Since then, hundreds of thousands of people have been killed and more than 10 million others displaced, according to UN officials.