By David Morgan and Sarah N. Lynch WASHINGTON (Reuters) - U.S. Republican and Democratic senators called on Sunday for a special bipartisan panel to investigate cyber attacks against the United States by foreign countries with a focus on Russia's alleged efforts to influence the U.S. presidential election. Charles Schumer, who will be Senate Democratic leader in the new U.S. Congress in January, and Republican John McCain, chairman of the Senate Armed Services Committee, said separately on Sunday a select committee was needed to ensure effective congressional focus on the hacking of Democratic Party emails during the campaign. Two other senators, Republican Lindsey Graham of South Carolina and Democrat Jack Reed of Rhode Island, joined Schumer and McCain of Arizona in sending a letter to Senate Republican leader Mitch McConnell requesting the panel.