The retired American general in charge of coordinating the U.S.-led coalition's fight against Islamic State militants is urging allies to do more to combat the group's extremist ideology.

Gen. John Allen's appeal came during a meeting of Western and Arab partners in Kuwait on Monday.

According to a transcript of his remarks, Allen says the IS group can only be defeated if coalition partners challenge its online presence and "deny the legitimacy of the message it sends."

Allen urged coalition members to lay out concrete plans to counter the militants' message online and in the press.

The IS group has seized large portions of Iraq and Syria and declared a self-styled caliphate, or Islamic state. It produces polished propaganda videos and promotes its activities aggressively on social media.