A deadly land mine explosion in Syria killed at least six people on Sunday, according to state media. News agency SANA said the explosion hit civilians who were foraging for truffles in the countryside, and blamed the incident on a land mine planted by the Islamic State group in the southern Deir Ez-Zor province. The area is a former stronghold of the militants. A day earlier, SANA reported six people - also heading to search for truffles - were killed by an anti-tank mine left by IS in the desert of Homs' eastern countryside. The Syrian Observatory for Human Rights, a Britain-based war monitor, put the number killed Sunday at nine. The monitor said the incident brings to 139 the number of civilians reported killed this year as a result of the explosion of mines and other explosive objects left over from the war, including 30 children. The truffles are a seasonal delicacy that can be sold for a high price. Since truffle hunters work in large groups in remote areas, IS militants have repeatedly preyed on them, emerging from the desert to abduct them, kill some and ransom others for money. In February, IS sleeper cells attacked workers collecting truffles near the central town of Sukhna, killing at least 53 people, mostly workers but also some Syrian government security forces.