A new video reportedly released by Islamic State extremists appears to show journalist Kenji Goto, the second of two Japanese hostages held by the group, being beheaded by a black-clad, masked individual.

The SITE Intelligence group relayed the video, which comes exactly a week after ISIS militants released a video featuring audio of Goto and a still photo showing him holding what appears to be a picture of the beheaded and lifeless body of fellow hostage Haruna Yukawa.

Japan had reportedly been conducting indirect negotiations with the kidnappers via ISIS militants in Iraq and/or Syria.

NPR's Alice Fordham, reporting from Beirut, says the executioner in the video appears to be the same British-accented jihadi that is thought to have killed American journalist James Foley and others.

In a narration, the man says:

"To the Japanese government. You, like your foolish allies in the satanic coalition, have yet to understand that we by Allah's grace are an Islamic caliphate with honor and power, thirsty for your blood."

To Japanese Prime Minister Shinzo Abe, the executioner says, "because of your reckless decision to take part in an un-winnable war, this knife will not only slaughter Kenji but will carry on and cause carnage wherever your people are found. So, let the nightmare for Japan begin."

The group had initially demanded $200 million in ransom from the Japanese government but subsequently changed its demand to the release of Sajida al-Rishawi, a failed female suicide bomber who has been in jail in Jordan since 2005.

ISIS is also believed to be holding a Jordanian pilot, Lt. Muath al-Kaseasbeh.

Update at 5:05 p.m. ET. NSC 'Working To Confirm' Video:

"We have seen the video purporting to show that Japanese citizen Kenji Goto has been murdered by the terrorist group ISIL," a statement by the White House's National Security Council said, referring to the Islamic State. "We are working to confirm its authenticity. 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."

Update at 6:31 p.m. ET. White House Releases Statement On Video:

The White House released a statement from President Obama Saturday evening, condemning what appears to be the murder of Japanese journalist Kenji Goto.

"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," the president said in the statement.

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