Abu Khayr al-Masri was killed when a missile fired from a drone hit the small car he was travelling in. The Egyptian militant was Osama bin Laden's son-in-law.
A US missile fired by a CIA drone killed Al Qaeda senior leader Abu Khayr al-Masri late on Sunday while he was riding in a car near the northwestern Syrian city of Idlib, a US intelligence official said on Wednesday.
The 59-year-old al-Masri, whose real name was Abdullah Muhammed Rajab Abdulrahman, was the second-ranking official after the group's leader, Ayman al-Zawahiri, and a member of its shura council, said the official, who was briefed on the attack and spoke on condition of anonymity.
He also was married to one of Osama bin Laden's daughters, the official added.
The official said Masri, as he was widely known, had sought refuge in Iran after the September 11, 2001, attacks on the United States, and was believed to have been in Syria helping to direct Jabhat Fateh al-Sham, an Al Qaeda branch previously called the Nusra Front, the official said.
The Iranians released him from house arrest almost two years ago, in exchange for a diplomat being held hostage in Yemen by Al Qaeda in the Arabian Peninsula, the official said.
An Iranian diplomat held hostage in Yemen since 2013 returned home to Tehran in 2015 amid conflicting accounts of how he was freed from his unidentified abductors.
At the time Iran said the diplomat had been rescued by an Iranian intelligence operation in Yemen. But Yemeni media run by the Iran-allied Houthi group said the diplomat was freed in a prisoner exchange that took place in another country.
Masri's death was the end of an almost 19-year US hunt for him.
A second US official, also speaking on condition of anonymity, said Masri was thought to be one of the planners of the 1998 attacks on the US embassies in Kenya and Tanzania.