An Israeli official declined to comment on reports of Asber's death when asked by the Reuters news agency.
A senior official from an intelligence agency in the Middle East has revealed that the assassination of one of Syria's most important rocket scientists Aziz Isber in a auto bomb explosion in the northern city Maysaf late Saturday was the handiwork of Israel's spy agency Mossad.
In Syria blew up a auto with Aziz Asbury, who was the head of the centre for the development of chemical weapons for the regime of President Bashar al-Assad.
Iran had also alleged Israeli involvement in assassinating four nuclear scientists: Masoud Alimohammadi, Majid Shehriari, Rezaeinejad and Mustafa Ahmadi roshan, between 2010 and 2012.
"Every day in the Middle East there are hundreds of explosions and settling of scores".
Under Israeli law, only the prime minister can authorize assassinations, termed "negative treatment" by Mossad.
Asbar headed the Maysaf research center in Hama, which was hit by Israeli air strikes last month and in September past year, the Observatory said. The attack, which took place in Masyaf, was at least the fourth assassination mission by Israel in three years against an enemy weapons engineer on foreign soil.
An Israeli air strike targeted the research centre on July 22, Syrian state media and the Observatory reported.
Israel has carried out numerous strikes inside Syria since 2017, according to the Observatory, targeting government forces and their allies from Iran and Lebanese Shiite militant group Hezbollah.
Syrian President Bashar al-Assad attends an interview with a Greek newspaper in Damascus, in this handout released May 10, 2018.