A flower lies atop names of victims at the 9/11 Memorial in New York on Sept. 10

A man linked to the Sept. 11, 2001, attacks on the United States, who was said to have praised "violent jihad," was captured in Syria by U.S.-backed forces more than a month ago, the Pentagon said on Thursday.

"We can confirm that Mohammad Haydar Zammar, a Syrian-born German national, was captured more than a month ago by SDF (Syrian Democratic Forces) partners as part of their ongoing operations to defeat ISIS inside Syria," Pentagon spokesman Eric Pahon said, using an acronym for Islamic State.

"We are working with our SDF partners to obtain additional details," Pahon said.