The US-led coalition is trying to verify reports that Fabien Clain, a Frenchman who is one of Europes most-wanted members of ISIS, has died in an airstrike in Syria. A French diplomatic official and an official with the US-backed Syrian Democratic Forces (SDF) said verifications are underway amid a standoff over the final sliver of land held by ISIS in southeastern Syria, close to the Iraqi border. Clain is considered a key figure in the November 2015 attacks in Paris, and it was his voice that claimed responsibility in the name of ISIS for the deadly onslaught in his home country. Neither official would be named, given the ongoing verifications in the village of Baghouz. A US military spokesman said the coalition could not confirm the reports. A French source close to the matter said that Clain had been killed and his brother Jean-Michel seriously wounded after a coalition strike on Wednesday in Baghouz. "Fabien was killed and his brother was seriously wounded in the operation," the source said. "There is a process of verification, but it is difficult to send someone on the ground. While there is no body, we have to remain prudent." The SDF, which has steadily driven the ISIS militants down the Euphrates, has surrounded the extremists at Baghouz but does not want to mount a final attack until all civilians are out.