Weekend airstrikes in Fallujah killed key figures in the network of suspected terrorist Abu Musab al-Zarqawi (search), a U.S. military official said Monday.

But Brig. Gen. Mark Kimmitt (search) declined to specify whether anyone killed in the strikes came from abroad.

The airstrike Saturday leveled a building that U.S. officials said was a suspected safehouse for the network of al-Zarqawi, a Jordanian-born militant believed to be linked to Al Qaeda. At least 16 people were killed in the strike.

"All of our post-strike intelligence continues to confirm that this was a safehouse with significant amounts of ammunition stored," there, Kimmitt said. "I will say more accurately that these were key personnel in the Zarqawi network."

A senior officer of the U.S.-backed Fallujah Brigade (search) has disputed the American contention, saying Sunday that rescue operations did not suggest any foreigners had been at the suspected safehouse.

The difference in U.S. and Iraqi assessments of the attack could strain relations between the Americans and the Iraqi security force established last month to take responsibility for law and order in Fallujah after the end of the three-week Marine siege.