A Marine statement also said U.S. and Iraqi forces destroyed a "foreign fighter safe house," killed two foreigners and arrested three others during a Tuesday raid in the same area as the bridge attack.
A Marine statement said F/A-18 jets dropped bombs shortly after midnight on two light bridges near Karabilah, about 185 miles west of Baghdad.
"The purpose of the strike was to prevent al Qaeda in Iraq terrorists from using the structures for vehicular traffic to conduct attacks," the U.S. statement said. "The munitions used in the strike were designed to crater the bridges, rendering them inoperable but not destroying them."
The clash at the safe house occurred when U.S. and Iraqi troops came under fire "by foreign fighters occupying" the building, the Marines said.
"Multinational forces personnel returned fire and assaulted the building, suffering one friendly casualty when a Multinational Force soldier was wounded," the statement said without citing the soldier's nationality.
Troops called in aircraft to destroy the building, "which was being used as an operational headquarters," the statement added.
In related developments:
Karabilah is one of a cluster of towns near the Syrian border, a major infiltration route for foreign fighters heading for Baghdad and other major cities. Iraqi officials say al Qaeda in Iraq, led by Abu Musab al-Zarqawi, has taken over parts of the area after residents fled fighting between tribes supporting and opposing the insurgents.
U.N. Secretary Genarl Kofi Annan told the British Broadcasting Corp. on Monday that many young Muslims are angry, and the situation has been exacerbated by what is happening in Iraq.
"They feel victimized in their own society; they feel victimized in the West. And they feel there's profiling against them," he said. "And the Iraqi situation has not helped matters."