STUTTGART, Germany -- U.S. forces targeted a mass of Islamic militants in Somalia on Tuesday in a self-defense airstrike that marks the second American attack in less than a week in the war-torn country.

U.S. Africa Command offered few details about the latest strike in the country where the military has stepped up operations, but did say the attack was about 300 miles southwest of the Somali capital of Mogadishu.

"This strike was conducted within the parameters of our authority to engage in collective self-defense of our Somali partners," AFRICOM said Wednesday in a prepared statement.

AFRICOM said it was still assessing the results of the attack and did not provide an estimate of how many militants were killed.

During the past year, AFRICOM has intensified operations against al-Shabab, a group that has resisted defeat despite the efforts of a wide-ranging international coalition of forces.

In March, President Donald Trump granted Marine Gen. Thomas Waldhauser, who leads AFRICOM, expanded authorities to launch offensive airstrikes against the terrorist group.

While those authorities haven't altered what military officials deem actionable intelligence on the battlefield, the expanded powers enable commanders to make decisions faster, AFRICOM officials have said.

On Sunday, U.S. forces also hit al-Shabab targets in a strike that was the second such attack under authorities granted by Trump. On June 11, AFRICOM also killed eight militants when it attacked a command outpost in Somalia's south, the military said.

"We continue to work in coordination with our Somali partners and allies to systematically dismantle al-Shabab, and help achieve stability and security throughout the region," AFRICOM said after Tuesday's strike.

Al-Shabab, which has operated for more than a decade in Somalia, has proven to be resilient in the face of international efforts to topple it.

Several years ago, the group was on the brink of overrunning Mogadishu, but efforts by a union of African militaries helped push the group out of its strongholds.

During the past year, al-Shabab has regrouped and picked up the pace of its operations.

For the United States, military efforts are expanding in Somalia, with trainers operating in the background and on the front lines with Somalia forces in hopes of building up the country's military institutions.

The effort to build a creditable Somali military could be a challenge in the clan-based country that has no history of possessing a strong central government.