Two American Air Force personnel were killed in a shooting attack Wednesday as they rode a bus outside the airport in Frankfurt, Germany.

The gunman is identified as Arif Uka, a 21-year-old man from Kosovo who may be living in the Frankfurt area. Uka was caught by airport security as he tried to run off. He comes from the northern Kosovo town of Mitrovica.

According to the New York Times, the victims were part of a busload of airmen who had just flown in from England. They were headed to the U.S. base at Ramstein when the suspect got on the bus. He reportedly asked the men who they were before opening fire. The newspaper cites a local businessman who spoke with witnesses after the attack.

They told him the shooter shouted "Allahu Akhbar," or "God is great" as he opened fire.

The two airmen killed, whose identities have not been released, were based in the U.K. At least two other people were wounded in the shooting.

Mitrovica has been described as "the hottest flashpoint in Kosovo." In an article last year, Stephen Schwartz of the Center for Islamic Pluralism detailed the growth of radical Islamist infiltration since the U.S. intervention there. Mitrovica, he wrote, was divided physically and politically by the Ibar River, which also separates its Serbian and Albanian communities.

In recent years, though, the city has seen an influx of radical Islamists who have targeted the community's established moderates. Schwartz quoted one local resident's complaint that "Foreign religion, foreign traditions appear among us like knives."