The head of a Syrian regime research facility was killed when his car was blown up, reported the pro-regime al-Watan newspaper on Sunday.
Aziz Asber was the director of the Syrian Scientific Research Center in Masyaf, near the city of Hama, which Western governments say was a covert regime installation.
Western countries say the facility was part of a chemical weapons program.
"(Asber) died after an explosion targeted his car in the Hama countryside," al-Watan said in an online report.
The explosion occurred on Saturday night, the Syrian Observatory for Human Rights war monitoring group said.
The attack on Asber was claimed by a Syrian rebel group affiliated to Tahrir al-Sham, a rebel group. It includes the group formerly known as the Nusra Front, which served as al-Qaeda's Syrian branch.
The Abu Amara Brigades released a statement on their Telegram online channel that said they "planted explosive devices" which detonated and killed Asber.
The Masyaf facility has previously been hit by what the regime said were Israeli strikes in July and last year in September.
In April, missile strikes by the United States, Britain and France destroyed a Syrian Scientific Research Center facility in Damascus, in response to a poison gas attack on the Douma enclave near the capital in April.
The regime, backed by Russia, has denied using or possessing chemical weapons despite wide suspicion of the contrary.
An Israeli government official declined to comment on reports of Asber's death when asked by Reuters.
Israeli Construction Minister Yoav Gallant, a member of Prime Minister Benjamin Netanyahu's security cabinet, speaking to Israel's Ynet TV said: "There is a war raging in Syria. A lot of sides are involved. There are a lot of interests ... I read about him in the newspaper.”
“He does not sound like a positive guy, to me."
