A gunman fired at U.S. Air Force personnel on a bus outside Frankfurt airport Wednesday, killing two airmen and wounding two others before being taken into custody, an Air Force spokesman in Germany said.
Air Force spokeswoman Maj. Beverly Mock said she could not release any further details on the victims until their next of kin have been notified.
Kosovo's interior minister told The Associated Press that German police have identified the gunman as a citizen of Kosovo.
President Obama told reporters he was "outraged" by the incident, adding it provided a "stark reminder" of the "sacrifices" made by U.S. military personnel.
German Chancellor Angela Merkel condemned the "terrible incident."
"We'll do everything possible to find out what happened," she said.
The attack came as the bus sat outside Terminal 2 at the airport, Frankfurt police spokesman Manfred Fuellhardt said.
At the airport, taxi cab driver Salimi Seraidon said he was sitting at a stand about 200 yards away when the attack took place, and that it was over quickly as police rushed onto the scene.
"We just heard the shots," he said.
Kosovo Interior Minister Bajram Rexhepi said in an interview that German police have identified the suspect as Arif Uka of the northern town of Mitrovica.
"This is a devastating and a tragic event," Rexhepi said. "We are trying to find out was this something that was organized or what was the nature of the attack." Spokesmen for the Pentagon and the Air Force in the U.S. had no immediate information on the incident.
While German police had no immediate information on what could be behind the shooting, a member of the U.S. House Homeland Security Committee, Rep. Patrick Meehan (R-PA), said in Washington that it looked like a terrorist attack.
The chairman of the subcommittee that focuses on terrorism and intelligence added that he did not have all the facts about the shooting yet and was still being briefed by his staff.
But German news agency DAPD quoted Hesse state's interior minister, who had rushed to the scene of the shooting, as saying that there were no indications of a terrorist attack.
The U.S. military has several bases in and around the greater Frankfurt region, some of which serve as logistical hubs for operations in Afghanistan and Iraq.
