"The United States condemns the heinous murder of Japanese citizen and journalist Kenji Goto by the terrorist group ISIL," Obama said in a statement yesterday.
An online video released last night showed an Islamic State militant behead Japanese journalist which ended days of negotiations by diplomats to save the man.
"Through his reporting, Goto courageously sought to convey the plight of the Syrian people to the outside world. Our thoughts are with Mr Goto's family and loved ones and we stand today in solidarity with Prime Minister Abe and the Japanese people in denouncing this barbaric act," he said.
"Standing together with a broad coalition of allies and partners, the United States will continue taking decisive action to degrade and ultimately destroy ISIL," Obama said.
Also Read
In a separate statement, the US Secretary of State John Kerry condemned ISIL's vicious murder of the Japanese hostage.
"We extend our sincere and heartfelt condolences to his wife, his family, and his loved ones, as well as to the people of Japan," he said.
"We share the sorrow and continue to stand shoulder to shoulder with our ally Japan in confronting terrorism. We commend Japan's support for those in the region who have been displaced by ISIL, the Syrian regime, and other militant groups," Kerry said.
"Japan's generous assistance to vulnerable communities fully reflects its commitment to international peace and development," he added.
Meanwhile in another statement, the National Security Council Spokesperson Bernadette Meehan said: The United States strongly condemns ISIL's actions and we call for the immediate release of all remaining hostages. We stand in solidarity with our ally Japan".
IS had said they will kill Goto and a Jordanian pilot Maaz al-Kassasbeh by sunset Thursday if Amman failed to hand over an Iraqi female jihadist.