WASHINGTON • The US military has bombed Islamic State in Iraq and Syria (ISIS) fighters in Somalia for the first time, a sign that the air campaign against the group is expanding after recent battlefield successes against the militants in Iraq and Syria.

Several militants were killed in a pair of drone strikes hours apart in the country's north-east on Friday, according to a statement from US Africa Command (Africom).

"US forces will continue to use all authorised 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.

According to Voice of America, which cited the chairman of the town of Qandala in the semi-autonomous region of Puntland, six missiles hit an ISIS base in Buqa village, 60km away. "Residents and pastoralists were shocked and fled," Mr Jama Mohamed Qurshe said.

Africom spokesman Lieutenant-Commander Anthony Falvo said no civilians were near the strikes. "They struck their intended targets," he said, noting these were the first anti-ISIS air strikes in Somalia.

The announcement of the new strikes came hours after US President Donald Trump said on Twitter that his administration had attacked ISIS "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.

ISIS has been gathering recruits in the region, although experts say the scale of its force is unclear and it remains a small player.

NYTIMES, AGENCE FRANCE-PRESSE, REUTERS