An al-Qaim hospital official, Muhammad al-Ani, said 35 people died in one house and another 12 in a strike on a second house.
Earlier, the US military said it had killed an al-Qaida fighter named Abu Islam and a number of other fighters in air strikes on Karabila, close to al-Qaim.
The US military gave no details of the total number of casualties.
According to the US statement, four bombs were used to destroy a house occupied by “terrorists” outside Husayba.
Two more bombs destroyed a second house in Husayba, occupied by Abu Islam, the statement added.
“Islam and several other suspected terrorists were killed in that attack,” the statement said, adding that the strikes began about 6.20am.
The statement said intelligence reports indicated that several of Islam’s associates fled from his house in Husayba for the nearby town of Karabila.
“Around 8.30am, a strike was conducted on the house in Karabilah using two precision-guided bombs,” the statement said.
“Several terrorists were killed in the strike but exact numbers are not known.”