The White House said on Tuesday that Iraqi troops' lack of will to fight Islamic State militants, an issue cited by the Pentagon chief over the weekend, has been a concern. "That certainly has been a problem that we have seen in the past," White House spokesman Josh Earnest ack**wledged when asked about Defense Secretary Ash Carter's comments on Sunday. Carter said Iraqi forces showed ** will to fight against Islamic State militants during the fall of Ramadi a week ago, and U.S. forces were trying to encourage them to engage more directly.