FRANKFURT/BERLIN (Reuters) - The gunman who shot dead two U.S. airmen in a U.S. Army bus at Frankfurt airport on Wednesday was probably a lone operator motivated by radical Islamist beliefs, German authorities said Thursday.
German media had reported the man could be part of a terrorist cell, raising the potential threat of further attacks on U.S. targets in Germany.
"He is a lone perpetrator according to our investigations so far," said Hesse Interior Minister Boris Rhein, adding there were no signs he belonged to a terrorist group. "There are reasons to believe that he is a radical Muslim."
Police arrested the man, who seriously wounded two further airmen, after the attack. Rhein said initial investigations had shown him to be willing to confess.
The gunman, identified as Arid Uka, is a 21-year old Kosovo national who was working on a short-term contract at the Frankfurt international postal center, authorities said.
Germany's new federal interior minister Hans-Peter Friedrich said the investigation was being carried out "at high speed" but there was no reason to increase security now.
"There is suspicion that the killing may have been motivated by Islamism," state prosecutors said, although not elaborating on the nature of the Islamism.
Media said the man, who visited Islamist websites and donned the fighter name "Abu Reyyan," shouted "Allahu Akbar" (God is Greatest) during the shooting.
President Barack Obama said Wednesday he was outraged by the attack and the Kosovo government condemned the shooting. The Kosovo parliament held a minute of silence.
The United States has had troops in Kosovo since 1999, when a NATO bombing campaign pushed out Serbian forces. The U.S. troops there now are helping to oversee a fragile peace that has held since Kosovo declared independence from Serbia in 2008.
Wednesday evening, people lit candles in Kosovo's capital Pristina and in the town of Mitrovica where the assailant is thought to be from. Kosovo newspapers said the attack had damaged the country's reputation.
The father of the gunman told Reuters Thursday that he was shocked by the attack, and apologized to the victims' families and the American people.
The U.S. embassy in Pristina however said "the act of a single individual will in no way affect the deep and abiding friendship between our two countries."
The U.S. Army bus had been transporting a team based in Britain from the airport to the Ramstein base, the U.S. airforce said. The team had been on its way to Afghanistan.
German Interior Minister Friedrich condemned the attack and expressed sympathy for the victims.
"It is painful because our closest allies were hit on our territory," he said. "At this hour, the government stands firm in its support for our American friends, and will do everything possible to work with American authorities to get to the bottom of this."
Friedrich, in his first news conference as interior minister, also said there was nothing in history to prove Islam belonged to Germany, contradicting President Christian Wulff who said last year Islam was now part of German society.
Additional reporting by Reuters TV, Brian Rohan and Hans-Edzard Busemann in Berlin, Marilyn Gerlach and Peter Dinkloh in Frankfurt, Fatos Bytyci in Pristina, Writing by Sarah Marsh