WASHINGTON/NAIROBI (Reuters) - The U.S. military said on Friday it had killed a woman and child in a 2018 airstrike in Somalia, the first time the military has acknowledged its strikes caused civilian casualties in the country.

U.S. Africa Command said the April 1, 2018, strike near El Burr, Somalia, had killed two civilians and four militants, not five militants as the U.S. military had originally reported.

Major General Gregg Olson, director of operations at U.S. Africa command, told reporters a subordinate organization of Africa Command had concluded by the summer of 2018 that civilians had been killed in the strike.

Olson said a “breakdown in reporting” led to the information not being passed to higher level commanders until recently.

In a statement, Africa Command said it believed the civilian fatalities were an “isolated occurrence.”

There has been increasing concern about the pace of strikes in Somalia and the civilian casualties that they may be causing. Amnesty International said last month it had documented 14 civilians killed in investigations of five airstrikes, a tiny fraction of those the United States says it has launched.

Africa Command said the April 1, 2018, strike was not one of those investigated by Amnesty and that it was committed to “credibility, transparency, and accountability.”

The U.S. military has carried out 28 airstrikes in Somalia in 2019, compared with 47 in 2018 and 35 in 2017. Most publicised strikes are followed by information on the number of militants believed killed.

While the strikes against al Shabaab militants have increased recently, it is unclear what lasting impact, if any, the strikes are having on the militant group.

Al Shabaab wants to overthrow the weak U.N.-backed Somali government and impose strict Islamic law.