Story highlights Dunford hopes to offer options for U.S. military action in the next few weeks

Action will be taken in conjunction with allies such as France, Italy and Britain

Washington (CNN) President Barack Obama's top military adviser has begun to talk openly about stepped-up U.S. military action against ISIS in Libya as the terror group expands its operations in the North African country.

The U.S. wants to "take decisive military action" to "check" ISIS in Libya, while still supporting the political process to form a functioning government, Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff, told reporters while traveling in Europe.

U.S. military reconnaissance flights over Libya and covert intelligence-gathering missions are now focusing sharply on tracking and locating ISIS's growing presence in that country, according to a senior defense official.

Dunford hopes to develop recommendations in the next several weeks that would offer options for U.S. military action in conjunction with allies such as France, Italy and Britain, the official said.

At the same time, Dunford is working on recommendations for additional U.S. and coalition troops to help the Iraqis retake the city of Mosul in the coming weeks and months.

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