OTTAWA—Canada is expected to face pressure this week to reverse a recent drawdown of troops from Iraq as the NATO military alliance prepares to expand its presence in the country. The alliance has persistent concerns about Islamic State extremists and Iranian-backed militias. NATO secretary-general Jens Stoltenberg predicted this week that defence ministers from across the alliance would approve the deployment of more trainers and advisers to help Iraqi security forces fight the Islamic State of Iraq and the Levant. Defence Minister Harjit Sajjan will be among those participating in the discussion during a two-day, closed-door meeting where he and counterparts from across the alliance will also discuss Afghanistan and the threats posed by China and Russia. “I expect ministers will agree to launch an expanded mission with more allied personnel training and advising in more security institutions across the country,” Stoltenberg said during a news conference on Monday. “The mission …