This is a developing story. For full coverage of the attacks on Paris, click here.
As the world continues to mourn the victims of the Paris attacks
, international leaders are turning their attention to fighting the group believed to be behind the bloodshed.
The Islamic State group, the terrorist network based in Iraq and Syria, has claimed responsibility for the coordinated assaults across Paris
that left more than 120 dead and hundreds more injured on Friday.
Although analysts say the attacks in Paris would be one of the most sophisticated ever committed by ISIS, the group has already demonstrated an ability to inflict violence across a broad area. On Thursday, the group claimed responsibility for a deadly bombing that killed more than 40 people in Beirut.
Fears about ISIS's extended reach were renewed on Monday, with the release of a video purported to be from the group that warns of attacks in Washington, D.C.
The video, which has reportedly not been verified by authorities, threatens continued attacks against all nations targeting ISIS with airstrikes
In the face of all this, international leaders are ramping up efforts to stop ISIS in its tracks.
Calling the attacks an "act of war," France launched a series of airstrikes
against ISIS targets in Syria over the weekend, as an international manhunt for a Belgian believed to be involved in the attacks continued. President Barack Obama vowed on Monday to do everything the U.S. can to "destroy this barbaric organization." Anonymous, the online "hactivist" group, has declared its own war on ISIS.
Click through for three crucial things you should know about ISIS and the fight against the terrorist network. For full coverage of the attacks on Paris, click here.