Reports say the militant group Islamic State has released a video in which it threatens it will attack Washington, D.C. The authenticity of the video could not be confirmed. It shows fighters holding weapons threatening to attack the U.S. In the video, a man wearing military clothes says,"I swear to God, a similar day that Paris went through, the U.S. will go through. We will strike the U.S. and its stronghold, Washington."

The Washington Post reported that the video looks similar to confirmed Islamic State videos. But the newspaper said it lacks the theatrics and high-quality editing that other videos have had.

On Friday, Islamic State fighters attacked six areas of Paris. The suicide bombings and shootings killed at least 129 people.

Meanwhile, an activist organization called Anonymous has said it will carry out cyber attacks against Islamic State. Anonymous is a group that hacks into websites and posts embarrassing information. It has hacked, or broken into, the accounts of individuals, governments and organizations of which it does not approve.