The ISIS group killed 15 people foraging for desert truffles in conflict-ravaged central Syria, while 40 others are missing, a war monitor said Friday. Syria's desert truffles fetch high prices in a country battered by 12 years of war and a crushing economic crisis. Since February, at least 150 people -- most of them civilians -- have been killed by ISIS attacks targeting truffle hunters or by landmines left by the extremists, according to the Syrian Observatory for Human Rights. "At least 15 people, including seven civilians and eight local pro-regime fighters, were killed by ISIS fighters who slit their throats while they were collecting truffles on Thursday," said Observatory head Rami Abdel Rahman. Forty others are missing following the attack in Hama province, he added. Syrian state media did not immediately report the incident. Between February and April each year, hundreds of impoverished Syrians search for truffles in the vast Syrian Desert, or Badia -- a known hideout for extremists that is also littered with landmines. Foragers risk their lives to collect the delicacies, despite repeated warnings about landmines and ISIS fighters. Earlier this month, ISIS fighters killed three truffle hunters and kidnapped at least 26 others in northern Syria, according to the monitor, which relies on a vast network of sources inside Syria. That attack happened near positions held by pro-Iran forces, said the Britain-based Observatory.