Mughnieh, in his mid-40s, was accused of killing more Americans than any other militant before the 9/11 attacks, and the bombings and kidnappings he is alleged to have organized are credited with ending American intervention in Lebanon under the Reagan administration.
He is believed to have overseen the April 1983 suicide bombing of the US Embassy in Beirut and, six months later, the twin suicide truck-bomb attacks against the US Marine barracks and the French paratroop headquarters in Beirut, acts that killed nearly 400 people.
As of Wednesday morning, no one had claimed responsibility for his death. But many in Lebanon and Syria blamed Israel, who is believed to have carried out these sorts of targeted assassinations in Beirut and Damascus before.
The late-night blast Tuesday tore apart Mughnieh's car, which was parked near an Iranian school in the Damascus suburb of Kfar Soussa. Syrian authorities have only confirmed that one person died in the blast.
Mohammed Habash, a Syrian Islamist lawmaker, said that Damascus needed more time to conduct an investigation before commenting publicly. "Israel is always aggressive and doesn't respect international laws and norms and it has proved in the past that it doesn't respect countries' sovereignty, whether in Palestine, Lebanon, or Syria."