The United States will not be able to meet a request to send more troops to Afghanistan from NATO's top commander there until next spring at the earliest, U.S. Defense Secretary Robert Gates said on Tuesday. “Without changing deployment patterns, without changing length of tours, we do not have the forces to send three additional brigade combat teams to Afghanistan at this point,” Gates told the Senate Armed Services Committee. “My view is that those forces will become available probably during the spring and summer of 2009,” he said. The United States now has about 33,000 troops in Afghanistan, including 13,000 under NATO command.