The attack occurred in the Mazzeh area, where there are several embassies and security buildings.
According to the British-based Syrian Human Rights Observatory (SOHR), the attack was directed at a building where several important members of the Lebanese Shia militia Hezbollah and the Iranian Revolutionary Guard had planned to meet.
Last week, the observatory reported that an Israeli attack on Mazzeh killed four people, including the son-in-law of the late Hezbollah leader Hassan Nasrallah, who was killed in an Israeli air attack on southern Beirut last month.
Iran and Hezbollah have been among the Syrian government's most important allies in the more than ten-year-long civil war in the country.
More than 400,000 people, most of them returning Syrian refugees, have made their way to Syria over the past two weeks to escape the intense Israeli airstrikes on Lebanon.
