U.S. Defense Secretary Robert Gates warned Congress on Sunday not to cut off funding for U.S. military involvement in Libya and predicted that the operation targeting Libyan leader Muammar Gaddafi's forces will "end OK." U.S. lawmakers question the legality of President Barack Obama's continued use of the U.S. military in Libya without the approval of Congress, Reuters reported. U.S. House of Representatives Speaker John Boehner, the top Republican in Congress, last week said Congress could cut funding for U.S. military involvement in Libya, ratcheting up pressure on Obama. Gates, who departs as Pentagon chief this month after serving in the post under one Democratic and one Republican president, noted that earlier during his stint in the job Congress also threatened to cut off funding for the Iraq war. "Frankly, I think cutting off funding in the middle of a military operation when we have people engaged is always a mistake," Gates told "Fox News Sunday." Speaking on the CNN's "State of the Union," Gates predicted a positive outcome of the NATO-led campaign in Libya. "We are seeing the Gaddafi government weaken," Gates said. "... I think this is going to end OK. I think Gaddafi will eventually fall." Gates added "my own bet" is that Gaddafi "will not step down voluntarily, but somebody will make that decision for him -- either his military or his family." Asked whether that meant someone would kill Gaddafi, Gates said, "Possibly." He said he could not make a prediction on how long it would take before Gaddafi falls. -- SPA