WASHINGTON - US President Barack Obama said on Wednesday he was outraged by an attack in Germany in which two US airmen were shot dead and two others seriously wounded.
"I am saddened and I am outraged by this attack that took the lives of two Americans and wounded two others," he said during a surprise appearance in the White House briefing room.
The Unites States will work with German authorities to investigate who was behind the attack, Obama said.
"We will spare no effort in learning how this outrageous act took place," he said.
Obama declined to take questions from journalists but said he would take questions from reporters on Thursday during a visit to the White House by Mexican President Felipe Calderon.
A gunman was in custody after the shooting of the troops in a US Army bus at Frankfurt airport. Boris Rhein, interior minister for the German state of Hesse, said the gunman was apparently a Kosovo national.