A U.S. aircraft on Sunday shot down a Syrian government fighter jet over northern Syria after it dropped bombs near U.S.-backed fighters, the Pentagon said.

The U.S. military said in a statement that President Bashar al-Assad's forces attacked the Syrian Democratic Forces in a town just outside of Raqqa on Sunday afternoon. U.S. officials used a "de-confliction channel" to contact the Syrian government in an attempt to de-escalate the situation.

Despite those efforts, a Syrian regime SU-22 dropped bombs near the U.S.-backed fighters at 6:43 p.m. and was immediately shot down by a U.S. F/A-18E Super Hornet, the Pentagon said in a statement. It was shot down "in accordance with rules of engagement and in collective self-defense of Coalition partnered forces."

Earlier Sunday, the Syrian army said the U.S.-led coalition shot down one of its aircraft during a combat mission against militants of the Islamic State of Iraq and Syria (ISIS).

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"The Coalition's mission is to defeat ISIS in Iraq and Syria," the statement said. "The Coalition does not seek to fight Syrian regime, Russian, or pro-regime forces partnered with them, but will not hesitate to defend Coalition or partner forces from any threat."

The U.S.-led coalition called on all parties in Syria's conflict to "focus their efforts on the defeat of ISIS, which is our common enemy and the greatest threat to regional and worldwide peace and security."