UNITED NATIONS, June 22 (Xinhua) -- UN Secretary-General Antonio Guterres has expressed grave concern over the recent military escalation in southwestern Syria, his spokesman said Friday.

The attacks, including ground offensives and aerial bombardments, have resulted in the displacement of thousands of civilians, the majority of whom are moving toward the Jordanian border, said Stephane Dujarric, the spokesman, in a statement.

The Syrian government forces are bent on retaking rebel-controlled southern areas in the country. Fighting and shelling were reported on Thursday in many towns on the eastern and western side of Daraa governorate, according to the UN.

On Wednesday, shelling and fighting in several areas of Daraa governorate reportedly killed 20 people, including 11 in Daraa city, and wounded many others.

The secretary-general is also concerned about the significant risks these offensives pose to regional security, Dujarric said.

"The secretary-general underscores the fragile situation of civilians in southern Syria. He calls for an immediate end to the current military escalation and urges all stakeholders to respect their obligations under international law and international humanitarian law, including the protection of civilians and civilian infrastructure," said the spokesman.

Recalling the de-escalation and cease-fire arrangements that have provided relative calm in southwestern Syria over the past year, Guterres urges all to exercise restraint and uphold these commitments as a matter of priority, he said.

In another development,the United Nations said earlier Friday that it was alarmed by reports of two vehicle-borne improvised explosions in the northwestern city of Idlib, which killed eight people, including a child, and wounded 40 others.

A car-bomb exploded near Idlib city's western entrance on Thursday. Shortly after the bombing, a bomb-laden motorcycle exploded in the same area.

An estimated 2.5 million people live in rebel-held Idlib governorate, nearly half of whom have been displaced by violence and are in need of humanitarian assistance, Haq told a press briefing.