Mohammad Reza Zahedi, a senior commander in Iran's Revolutionary Guards Corps (IRGC), was among the 8 killed in the attack, according to a Lebanese security source speaking to news agency Reuters.
The official news agency SANA said the strike hit the building in the Mazzeh neighborhood. Syria's Defense Ministry confirmed the attack, saying there were casualties but did not provide a specific number.
Local Iranian media reported the strike completely destroyed the annex building. Iranian news agencies said Ambassador Hossein Akbari and his family were unharmed.