Seeking experience in wartime, President-elect Barack Obama intends to retain Defence Secretary Robert Gates as head of the Pentagon, if only temporarily, and has chosen a retired Marine general to be White House national security adviser, officials have said. Gates and retired Gen James Jones would bring decades of experience to the administration of a 47-year-old commander in chief who campaigned on a pledge to withdraw combat troops from Iraq within 16 months while simultaneously ramping up the US military presence in Afghanistan. While Gates has accepted Obama's appointment, it was not clear that Jones had done the same.