U.S. tightens Libya sanctions; key senators back Obama WASHINGTON (Reuters) - 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. feeds.reuters.com/~r/Reuters/PoliticsNews/~3/uUB2MBiHt8U/us-libya-usa-idUSTRE75K5WQ20110622