The Islamic State has published photos online of military gear and identification cards allegedly taken from American troops serving in Afghanistan.

The photos show ammunition, weapons and communications equipment, as well as the American flag. They also show someone holding a U.S. military ID belonging to Spc. Ryan Jay Larsen.

Site Intelligence Group, which tracks terrorist activity online, placed the pictures on Twitter on Saturday and wrote that they had been posted by the Amaq News Agency, which is run by the Islamic State. The tweet said the equipment had been taken in Nangahar Province, Afghanistan.

A Pentagon spokeswoman said Larsen had been accounted for and not captured by the Islamic State.

"We can confirm that the soldier in question is with his unit and is not captured, despite having lost his ID card and possibly some of his equipment during recent operations," Henrietta Levin said in a statement. "We are still working to determine if all of the equipment in the pictures was lost during recent operations or at some other time in the past.‎"

American special operations are operating in Nangahar Provence, according to the Military Times.

A former leader of a special operations unit in Afghanistan told the Military Times that the type and amount of equipment in the pictures suggests that the Americans were forced to leave their gear behind in a hurry.

"From the looks of all of this," Fred Galvin, a retired Marine Corps officer, said, "it appears [the perpetrators] may have hit a fixed position. Maybe they ran across an observation post, or a site where guys were sleeping, bedding down. You can't tell 100 percent. But it does look like someone was caught in a hasty attack. If they knew they were going to be attacked like that, they would have been wearing their body armor."