Most Americans, even if they don’t follow the Afghanistan war closely, are familiar with al Qaeda, who was behind the Sept. 11 attacks, and the Taliban, who gave its leader Osama bin Laden safe haven. They might even have heard of the Haqqani network, a Taliban splinter group, responsible for terror attacks in Afghanistan and based over the border in Pakistan.

But this week, the U.S. announced it was targeting another cross-border terrorist group, the East Turkestan Islamic Movement, or ETIM, which operates in the border region with China and Tajikistan.

A statement from the NATO-led operation Resolute Support said that U.S. airstrikes in Afghanistan’s northern Badakhshan province Thursday destroyed training camps and other fighting positions that supported operations conducted by both the Taliban and ETIM.

The group has been designated as a terrorist organization by the U.S., Britain, China, Afghanistan, Kyrgyzstan, and the United Nations, and has roots in China’s Uighur minority, a mostly Muslim Turkic-speaking people who inhabit the Xinjiang region in China’s far west.

“They're a terrorist organization that operates in China and the border regions of Afghanistan,” Maj. Gen. James Hecker told reporters at a Pentagon briefing Thursday. “ETIM enjoys support from the Taliban in the mountains of Badakhshan, so hitting these Taliban training facilities and squeezing the Taliban's support networks degrades ETIM capabilities.

“ETIM militants have fought alongside al-Qaeda and Taliban forces in Afghanistan, and are responsible for various terrorist acts inside and outside China,” the U.S. military said in a statement.

“In May 2002, two ETIM members were deported to China from Kyrgyzstan for plotting to attack the U.S. Embassy in Kyrgyzstan,” the statement said. “They pose a threat to China and enjoy support from the Taliban in Badakhshan and throughout the border region.”

Thursday’s strikes on training camps in the rugged mountains of Afghanistan's border region were carried out by a U.S. B-52 long-range heavy bomber, which used precision weapons to take out three separate camps.

“We didn't actually strike ETIM terrorists when we were doing this,” Hecker said. “We were strictly striking the training camps that both the Taliban as well as the ETIM use."

“ETIM seeks to separate the Uighur people, an ethnically and religiously unique group, from China to create ‘East Turkestan,'” according to the Project on Violent Conflict at the State University of New York.

Hundreds of people have been killed in violence in Xinjiang in recent years, which the Chinese government blames on ETIM, supported by al Qaeda and the Taliban.

The U.S. targeted leaders of the group with drone strikes in Afghanistan in 2010 and 2012. But in both cases, the men thought to have been killed turned up later, wounded but still alive.