Pentagon officials say they believe a top bomb-maker for a cell of al-Qaida jihadists was killed in a U.S. airstrike in Syria earlier this summer.

The death of David Drugeon, a French-born member of the Khorasan group of al-Qaida veterans, would be a significant setback for the organization.

A Pentagon official said Friday that intelligence analysts believe Drugeon was killed in a July airstrike that also killed a key leader of the Khorasan group, which is a cadre of al-Qaida operatives using Syria as a sanctuary for plotting attacks on the West. The official spoke on condition of anonymity because the assessment that Drugeon likely was killed has not been announced publicly.

French officials say Drugeon spent time with al-Qaida in the tribal areas of Pakistan before traveling to Syria.