Al Qaeda terrorists reportedly declared war on the Islamic State Monday following a “dispute” between the groups over a prisoner exchange with the Lebanese army.

The two competing terror organizations are at odds with one another, with clashes erupting along the Syrian and Lebanese borders, Iran’s state-controlled Fars News Agency reported, citing “sources.”

Iranian forces also have been working to combat Islamic State militants in Syria and Iraq and have sent hundreds of fighters to the region.

“Heavy fighting” between the Islamic State and the al Qaeda-aligned al-Nusra Front erupted in Syria last week, “leaving casualties on both sides.”

Multiple clashes between the two terror groups over the past several months are said to have left many dead on each side of the battle and widened “rifts” between the sides.