Jihadi members of the Islamic State (ISIS/ISIL) branch in Afghanistan are using civilians as shields and “dressing in female attire” to escape a counterterrorism offensive, U.S. forces in Afghanistan (USFOR-A) said in a statement.

The statement came as reports emerged earlier this week saying an airstrike that targeted the Islamic State on Wednesday killed at least 15 civilians and wounded at least 13 others, including at least one child.

Earlier this year, U.S.-backed Afghan National Defense and Security Forces (ANDSF) launched an ongoing offensive against the Islamic State branch in Afghanistan, known as the Khorasan Province (IS-KP/ISIL-K).

The U.S.-backed ANDSF are focusing on combating ISIL-K in their regional stronghold — eastern Afghanistan’s Nangarhar province, located along the country’s border with Pakistan.

Gen. John Nicholson, the top commander for U.S and NATO troops in Afghanistan, told reporters nearly a week ago that an estimated “1,200 to 1,300” ISIL-K members remain in Afghanistan, down from a peak of nearly 3,000.

In a statement, the U.S. military in Afghanistan said:

Daesh [ISIL-K] is killing innocent Afghan men, women, and children. They continue to put innocent lives at risk by deliberately surrounding themselves with civilians and dressing in female attire. We have repeatedly said that we will target Daesh wherever they are in order to disrupt their operations, degrade their attack networks, and protect innocent lives.

It added:

Our Afghan partners, especially their special forces, have been working diligently to disrupt and destroy Daesh in Southern Nangarhar, and we continue to work alongside them to support their efforts. The ANDSF have significantly reduced Daesh presence and inflicted hundreds of casualties on them. In addition and as part of US unilateral counter-terrorism operations, US forces also killed their leader in Afghanistan, Hafiz Sayed Khan, in late July.

Regarding the strike in Nangarhar that resulted in civilian casualties, the U.S. military said it was investigating the incident.

USFOR-A said:

We won’t discuss the details of the specific counter-terrorism operation conducted in Nangarhar on 28 September because we are still reviewing all materials related to the strike. We take every possible measure to avoid civilian casualties in these operations, and will continue to work with Afghan authorities to determine if there is cause for additional investigation as we partner with the Afghan government in the broader fight against terrorism.

The United Nations Mission in Afghanistan, or UNAMA, condemned the strike in a statement.

Nangarhar province borders Pakistan. It became the Islamic State’s stronghold in Afghanistan soon after the group established its presence in January 2015, less than a month after U.S. President Barack Obama and NATO ended their combat mission and reduced their military presence in the country.

The U.S. military has since returned to combat operations, despite claims to the contrary by the Obama administration.

“Nangarhar province has been a focus for Daesh activity since 2015. Daesh seek to use the area to train, equip, disseminate propaganda, and expand their control over innocent Afghans,” stated the U.S. military in Afghanistan.