Desk Report:  The United States on Tuesday tightened financial sanctions on the Libyan government and two influential senators pushed back against calls to halt funding for American involvement in Nato operations there.

Senators John Kerry and John McCain introduced a measure to formally authorize the US military intervention in Libya for up to one year, and warned against critics who want Congress to act to stop US involvement.

A Senate vote would send a message that Washington was committed to the conflict and would not abandon allies who are leading it, Kerry said. Pulling the plug would “doom the Libyan operation” and “undermine the very core of Nato,” he warned.

The US Treasury said it was blacklisting nine companies owned or controlled by Muammar Gaddafi’s government.

The sanctions will prohibit US transactions with the nine companies, including the Arab Turkish Bank, Tunisia-based North Africa International Bank and Lebanon-based North Africa Commercial Bank, the department said.

The Treasury also removed sanctions against former oil minister Shukri Mohammed Ghanem because he defected from Gaddafi’s government in May.

Earlier this year, the United States lifted sanctions against former Libyan foreign minister Moussa Koussa, who fled to Britain on March 30, in an attempt to persuade other officials in Gaddafi’s government to defect.

“To the extent that sanctioned individuals distance themselves from the Gaddafi regime, these measures can be lifted,” Adam Szubin, the director of Treasury’s Office of Foreign Assets Control, said in a statement.

Kerry and McCain were responding to criticism from some lawmakers in both parties that US involvement in the Nato attacks, mainly confined to logistical support and intelligence, is illegal because it has not been endorsed by a vote in Congress. The United States has also launched predator drone strikes on Libyan forces.

Nato is leading the United Nations-sanctioned mission to protect Libyan civilians from Gaddafi’s forces. It has become a predominantly air campaign whose unstated goal appears to be to drive the Libyan leader from power.

Kerry, a Democrat, and McCain, a Republican, argued against efforts in the House of Representatives to cut off funds for US engagement. This would “snatch defeat from the jaws of victory,” Kerry said on the Senate floor.