WASHINGTON — The United States military bombed Islamic State fighters in Somalia for the first time on Friday, a sign that the air campaign against the group was expanding after recent battlefield successes against the militants in Iraq and Syria.

Several militants were killed in a pair of strikes hours apart in the country’s northeast, according to a statement from United States Africa Command.

“U.S. forces will continue to use all authorized and appropriate measures to protect Americans and to disable terrorist threats,” the statement said, adding that the strikes were carried out in coordination with the Somali government.

The announcement of the new strikes came hours after President Trump said on Twitter that his administration had attacked the Islamic State “much harder” over the past two days. It was not immediately clear what he was referring to — the larger air campaign against the extremists in Iraq and Syria remained steady, according to the military — but the announcement of the bombings in Somalia helped clarify his statement.