WASHINGTON (AFP) - The US military is looking at doubling the size of Afghan security forces but the option has not yet been approved by the US government or Nato allies, a US general said on Tuesday. The officer in charge of training Afghan forces, General Richard Formica, confirmed that the military in an initial assessment weighed a much larger security force. Weve looked at numbers that come close to nearly doubling, not quite doubling, both the army and the police, Formica told reporters by video link from Kabul. Its not been vetted in Washington nor by our coalition partners, said Formica, referring to the larger force size. The General declined to say precisely if doubling the security force was a reference to the initial target for Afghan forces. But US officials have confirmed reports that the administration considered a combined security force of about 400,000, roughly doubling the planned target. He said Obama last week had left the door open to further expanding the Afghan army and police.