Two leading U.S. senators have introduced a resolution that would limit the role of the U.S. military in Libya.

Foreign Relations Committee Chairman John Kerry, a Democrat , and a leading Republican, John McCain , unveiled the measure Tuesday.

The resolution would impose a one-year limit on U.S. military involvement in the NATO coalition in Libya, and prevent the use of American ground troops in the conflict.

But both senators cautioned against abandoning the U.S. mission at this time, saying Libyan leader Moammar Gadhafi is close to losing his grip on power. They also argued against efforts in the House of Representatives to cut off funding for the operation.

The White House said it welcomes eventual passage of the Senate resolution.

McCain also disagreed with the decision by U.S. President Barack Obama to order military operations in Libya three months ago without seeking congressional approval.

The president has been criticized by Republican and Democratic lawmakers for not seeking congressional authorization to intervene in the conflict.

Separately, the U.S. Treasury Department tightened sanctions against the Libyan government by prohibiting U.S. transactions with nine companies for being owned or operated by Mr. Gadhafi's government.

The Treasury Department also removed sanctions against former Oil Minister Shukri Mohammed Ghanem because he defected from Mr. Gadhafi's government last month.