As the United States begins to deepen ties with moderate Syrian rebels to combat the extremist group ISIS, also known as the Islamic State, a key component of its coalition appears to have struck a non-aggression pact with the group.

According to Agence France-Presse, ISIS and a number of moderate and hard-line rebel groups have agreed not to fight each other so that they can focus on taking down the regime of Syrian President Bashar Assad. Other sources say the signatories include a major U.S. ally linked to the Free Syrian Army.