A Twitter account run by an Qaeda member said the leader of the al Qaeda-linked Khorasan group was killed in a U.S. air strike in Syria, SITE monitoring service said on Sunday, following several days of uncertainty over whether he survived the raid.

A U.S. official on Sept. 24 said the United States believed Mohsin al-Fadhli, a senior al Qaeda operative, had been killed in a strike a day earlier, but the Pentagon said several hours later that it was still investigating what had happened to him.

In a message posted on Sept. 27, the jihadist offered condolences for the death of Kuwaiti-born Fadhli, otherwise known as Abu Asmaa al-Kuwati or Abu Asmaa al-Jazrawi, following the Sept. 23 air strike, SITE reported.