The US House of Representatives has dealt a symbolic blow to American military intervention in Libya by rejecting a resolution to authorise operations for one year.
The US role in the NATO mission has drawn criticism from many in Congress in recent weeks, the BBC reports.
Opponents say the three-month-old operation requires Congress's approval.
However President Barack Obama informed Congress last week that administration lawyers deemed the Libya conflict did not require additional congressional approval, arguing US forces were merely playing a supporting role in the NATO campaign.
A second resolution, which aimed to limit funding for American military operations in Libya, has been rejected.
