Foreign fighters from Britain, Sweden and Pakistan were among those killed by US missiles and Somali army operations, according to the Somali government.
A remote village in the Puntland region was bombarded on Friday, following the reported arrival of foreign militants.
As many as a dozen people were reported to have been killed, including at least six foreign Islamists, the government and army said.
The US has launched several strikes on alleged militants in Somalia this year.
The latest was carried out by a US warship off the coast, and aimed at hills around the village of Bargal, the government said.
The United States has refused to comment on the action.
"Foreign fighters, Somali militants and members of the international terrorists including British nationals, Americans, Swedish, Pakistanis and Yemenis were killed in separate operations carried out by Puntland troops and US Navy forces," the Puntland regional government said in a statement.
"The terrorists, who arrived in Puntland's mountainous area of Bargal with boats from southern Somalia, have been defeated," the statement said.
Five government troops were injured in the operation, it said.
The claim was denied on a website used by Islamists.
"American planes carried out random attacks without causing any losses among the mujahideen, praise to God," a group calling itself the Young Mujahideen Movement said in the statement.
It also claimed 11 soldiers were killed.
Until now fighting between rival clan militias and remnants of Islamist militants, who seized control of large parts of Somalia for six months of 2006, has been concentrated in the south of the country.
This is the first time the US has launched an attack in the Puntland region, home to Somalia's President Abdullahi Yusuf, says the BBC's East Africa correspondent Karen Allen.
US media reports suggest the target was an al-Qaeda operative suspected of involvement in the 1998 bombings of US embassies in Kenya and Tanzania.