A U.S. military airstrike killed 17 people allegedly affiliated with ISIS in southwest Libya, the military announced Friday—the third strike against militants there this month.

The strike was carried out Thursday by U.S. Africa Command (AFRICOM) in conjunction with the U.N.-backed Libyan Government of National Accord. AFRICOM said it did not believe any civilians were injured or killed. This month’s strikes in Libya are the first in more than a year by the U.S. military, according to the Associated Press.

“This ongoing campaign against ISIS-Libya demonstrates that U.S. Africa Command persistently targets terrorist networks that seek to harm innocent Libyans,” said Navy Rear Adm. Heidi Berg, director of intelligence at AFRICOM. “We will continue to pursue ISIS-Libya and other terrorists in the region, denying them safe haven to coordinate and plan operations in Libya.”

AFRICOM told TIME that for “operational security reasons” it could not disclose whether the coordinates for the airstrike came from U.S. or Libyan intelligence services. “It is important to preserve operational advantage and not signal to these terror elements when, where, and the various means available to disrupt them,” a spokesperson said in an email.

An airstrike on Tuesday killed 11 people and a strike Sept. 19 killed eight—all associated with ISIS, AFRICOM said.

Human rights groups have not called the lack of civilian deaths in Thursday’s strike into question. But the U.S. military has understated civilian death tolls in the past.

The U.S.-led coalition in Syria killed more than 1,600 civilians during the bombardment of Raqqa, Syria in 2017, according to an investigation by Amnesty International and Airwars. The U.S. has publicly admitted responsibility for only 10% of those.

“There has never been a more precise air campaign in the history of armed conflict,” the commander of the Raqqa operation, Gen. Stephen J. Townsend, wrote at the time. Since July 2019, Townsend has been the commander of AFRICOM.

Donatella Rovera, senior crisis adviser at Amnesty International who led the investigation, suggested Thursday’s airstrike in Libya should be investigated.

“I work on the basis that cases need to be investigated,” she told TIME. “It may be that their [AFRICOM’s] version of events in Libya is totally accurate, I don’t know. I can tell you about the hundreds of cases I investigated in Syria and Iraq where their version of events was not accurate at all, in a very large number of cases, including practices that they themselves boasted about, notably General Townsend … honestly some of the statements that he made were really baffling.”

The Libyan Government of National Accord, based in the northwest of the country, is currently fighting forces led by Khalifa Haftar, a strongman and U.S. citizen who rose to prominence in the northeast of the country amid the civil war that followed the death of former Libyan leader Muammar Gaddafi.

Recent U.S. strikes against ISIS in Libya have been confined to the sparsely-populated southwest, away from the conflict between Haftar and the Government of National Accord. But ISIS has also been present in the north of the country in the past.

“U.S. Africa Command continues to support diplomatic efforts to stabilize the political situation in Libya in order to maintain our common focus on disrupting terrorist organizations that threaten regional stability,” AFRICOM said in a statement.