Story highlights US forces have been fighting in an ISIS stronghold in Afghanistan for weeks

The photos show ammunition, fabric packs and possibly a shoulder-fired rocket launcher

(CNN) Several items of US military equipment displayed by ISIS in photos published over the weekend likely was either found or captured after recent battles in eastern Afghanistan, according to a senior defense official.

US forces, including many special operations forces, have been fighting in Afghanistan's Nangahar Province, a stronghold of ISIS for the last several weeks.

The photos, distributed by ISIS's media arm, depict ammunition, fabric packs and possibly a shoulder-fired rocket launcher of the type used by US forces.

While the Pentagon declined to confirm that the items in the photos belong to the US military, the official said, "We think much of the equipment was likely lost during recent operations."

Read More