The House of Representatives of the U.S. Congress voted down on Friday a resolution giving President Barack Obama the authority to order military action in Libya.
Lawmakers rejected the resolution by a vote of 295 to 123.
But the House on Friday also voted down a Republican bid to halt funding for the conflict.
U.S. lawmakers have repeatedly expressed their dissatisfaction with Obama's violation of the War Powers Resolution, a Vietnam-era law that restricts the presidential power of unleashing war without Congress's permission.
However the White House said it did not need the approval of Congress since the United States is simply supporting NATO.
Libya has been rocked with protests against longtime leader Muammar Gaddafi since mid-February. The international military operation Unified Protector began on March 19 following a UN resolution.
Fourteen of the 28 NATO countries are taking part in the Libyan military campaign, which includes airstrikes, a no-fly zone and naval enforcement of an arms embargo in response to attacks on civilians.
Russia abstained from the Security Council vote authorizing the NATO-led military operation, and has strongly criticized the alliance's handling of the operation.