US Defense Secretary Robert Gates has endorsed a new five-year, $17 billion plan to increase the size of the Afghan army by about 50,000 troops. The move follows a proposal from the Afghanistan government, and the price tag includes the costs for routine Afghan Army combat operations and upgrading the air corps, beginning in 2010, Pentagon press secretary Geoff Morrell said Friday. He said it generally costs about $1 billion a year to increase forces by 10,000, and another $100,000 to sustain them. Officials are currently looking at ways to finance it. Options include seeking money from NATO allies.