Afghan Defence Minister Mohammad Rahim Wardak backed US plans to send more troops to Afghanistan to help ensure security until the national army is ready to take over. "There is a gap that has to be breached (until Afghan troops can take over) and there will be a requirement of international forces," he told a panel at the Davos forum. US President Barack Obama is reviewing Afghan policy after receiving a request from the US commander in Afghanistan, General David McKiernan, for a 30,000-troop buildup.