"Nine citizens were killed and two others injured... in the eastern countryside of Al-Salamiyah", in the central province of Hama, when a landmine left behind by Islamic State group militants blew up under their car, the official SANA news agency said.

The Syrian Observatory for Human Rights war monitor said the victims had been hunting in the desert for truffles, a delicacy that can be sold at exorbitant prices.

On February 18, at least 68 people picking truffles in a desert of neighbouring Homs province were killed in a suspected IS attack, said the Observatory, which has a wide network of sources inside Syria.

The Britain-based monitor said IS was taking advantage of the annual harvest of the desert fungus, which is in season from February to April, to carry out attacks in remote locations.

Truffle digging has seen many people, including women and children, lose their lives in the country's central, northeastern and eastern regions in recent years.

Explosives left in fields, along roads or even in buildings by all sides in Syria's 12-year conflict have wounded killed hundreds of civilians and wounded thousands more, according to the Observatory.

Across Syria, more than 10 million people live in areas contaminated by explosive hazards, the United Nations has said.

Syria's war has claimed the lives of around half a million people and displaced millions since it erupted in March 2011 with the brutal repression of anti-government protests.