A White Helmets member uses a saw on rubble after an airstrike in in Idlib, Syria on Tuesday. Reuters

• Russia-backed government forces last summer retook the province
• It was not immediately clear who was behind the blast
• At least 12 people were killed and scores wounded on Tuesday in aerial strikes

A blast killed six soldiers in southern Syria on Wednesday in a rare such deadly attack in the defeated cradle of the eight-year uprising, a war monitor said.

"The explosive device was aimed at a convoy transporting members of the Fourth Division" in the southern province of Daraa, the Syrian Observatory for Human Rights said.

A Syrian rescuer runs during airstrikes by Syrian regime forces in Maar Shurin on Tuesday. Abdulaziz Ketaz/AFP

Fifteen others were also wounded in the attack near Yadud village, some seven kilometres (four miles) outside the provincial capital of Daraa city, the Britain-based monitor said.

Regime air raids kill 11 in northwest Syria says monitor

It was not immediately clear who was behind the blast, but loyalists in the province face explosions and gunfire on a near daily basis, although they are usually not deadly, it said.

"Previous rebel fighters who call themselves the Popular Resistance usually carry out these types of attacks against the regime," Observatory chief Rami Abdel Rahman said.

State news agency SANA said "terrorists targeted a military vehicle on the Yaduda road", reporting an undefined number of "dead and wounded".

Russia-backed government forces last summer retook the province, following a deadly bombardment campaign and surrender deals that saw part of the population board buses to an opposition holdout region in the northwest.

Government institutions have since returned, but army forces have not deployed in all of the province.

Syrian air strike

At least 12 people were killed and scores wounded on Tuesday in aerial strikes believed to have been carried out by the Syrian air force on a popular market in a village in opposition-held northwestern Syria, rescuers and residents said.

Residents and rescuers said bombs dropped on Maar Shoreen village in southern Idlib province by planes which monitors said were Syrian army jets left a trail of death and destruction and wounded scores in a main street of the village's market.

A motorbike burns after an airstrike in this screen grab taken from a social media video said to be taken in Idlib. Reuters

Videos released on social media by activists purportedly showed footage of charred bodies lying on the streets alongside badly burnt people being carried by rescuers. Reuters was unable immediately to independently verify the footage.

Hundreds of civilians have been killed since a Russian-led assault on the last rebel bastion in northwestern Syria began nearly two months ago, rights groups and rescuers said.

Agencies