A top U.S. government lawyer has defended President Barack Obama's decision to intervene in Libya, saying the administration is acting “lawfully.”

Testifying before the Senate Foreign Relations Committee Tuesday, State Department legal adviser Harold Koh said the situation in Libya does not constitute a war requiring specific congressional approval under the Constitution.

He argued that because of its limited nature, U.S. military support for the NATO-led mission against Libyan leader Moammar Gadhafi does not fall under the 1973 War Powers Resolution. The act requires congressional approval within 60 days when U.S. forces are involved in hostilities.

President Obama's assertion that the three-month-old Libya campaign does not constitute “hostilities” has divided lawmakers.

The chairman of the Foreign Relations Committee, Democrat John Kerry, said he believes the 60-day war powers restriction does not apply to U.S. involvement in Libya, pointing out that no American troops are on the ground or being shot at in the country.

But Republican Senator Richard Lugar said President Obama's decision not to seek congressional authorization was, in his words, a “fundamental failure of leadership that placed expedience above Constitutional responsibility.”

Later Tuesday, the Senate committee is scheduled to consider a resolution that would give President Obama limited authority of one year for U.S. involvement in NATO operations in Libya, while preventing the use of American ground troops in the conflict.

Senator Kerry and Republican Senator John McCain introduced the resolution. Both lawmakers cautioned against abandoning the U.S. mission, saying Mr. Gadhafi is close to losing his grip on power.

Senator Lugar plans to propose five amendments to the measure that would further restrict President Obama's authority.