Story highlights The designation applies to what the U.S. now calls ISIS-K (ISIS-Khorasan), which is the ISIS branch in Afghanistan and Pakistan

According to U.S. officials, the change now means that U.S. forces can actively pursue ISIS elements and attack them as a threat to the United States

Washington (CNN) The Pentagon has now been granted new legal authority allowing the military go on the offensive against ISIS in Afghanistan.

When the State Department announced the designation of ISIS in Afghanistan and Pakistan as a Foreign Terrorist Organization last week, it led to a change in the rules of engagement for U.S. forces, according to defense officials. The development was first reported by The Wall Street Journal.

The designation applies to what the U.S. now calls ISIS-K (ISIS-Khorasan) , which is the ISIS branch in Afghanistan and Pakistan. ISIS-K already is believed to be responsible for suicide and small-arms attacks and kidnappings, targeting civilians and Afghan government officials.

According to U.S. officials, the change now means that U.S. forces can actively pursue ISIS elements and attack them as a threat to the United States. Previous rules of engagement required ISIS elements to first pose a threat to U.S. forces in the area or to be pursued as part of a specific counterterrorism mission, officials said.

The consequence of the State Department designation is that there is a prohibition against knowingly providing, or attempting or conspiring to provide, material support or resources to this organization.

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