An Israeli government spokesman declined to comment on the allegations.
Syrian press reports blamed Israel's Mossad intelligence agency for the killing and said Asbar had survived two previous assassination attempts, also by Israeli agents, according to the New York Times.
Asbar, the research director at Syria's Scientific Studies and Research Center, was believed to be developing a secret weapons manufacturing facility with the help of Iran, which was to be used to manufacture precision-guided missiles in Syria.
The Syrian Scientific Research Centre has always been a focus of global efforts to curtail Syria's capacity to develop weapons of mass destruction, including chemical and biological weapons.
Khamenei says Iran does not have anything to be concerned about
The Trump tactics have deepened an already serious economic crisis in Iran, fuelling protests around the country. Trump said Monday that he was open to new talks to reach a " more comprehensive deal" with Iran.
In an interview on army radio on Tuesday, Israel's Intelligence and Transportation Minister Yisrael Katz welcomed Asbar's "departure from the world". He was also collaborating with Iranian Maj.
Israel's Hadashot TV news said Sunday night that he was in charge of a project improving the range and accuracy of the regime's Scud missiles. The official said Mossad had been tracking Asbar, who was allegedly in charge of re-building an underground weapons factory that the Israeli military destroyed a year ago. He claimed that it was the fourth time in three years the Mossad has assassinated an enemy weapons engineer in a foreign country.
In April, coordinated missile strikes by the United States, Britain and France destroyed a Syrian Scientific Studies and Research Centre facility in Damascus, in response to a suspected gas attack that killed at least 70 civilians in Douma - a town in the former rebel-held city of Eastern Ghouta. The group has previously claimed attacks targeting officials and militia commanders inside government territory.
His work was involved most with the Bashar al-Assad government along with possible ties with the Hezbollah movement and Iran.