The battle for Tikrit is being conducted by a mixed coalition of Iraqi forces, Shiite militias, and air cover from Iraqi forces, AFP reports.
AFP reporting “Overseeing all of this is General Suleimani, one of Iran's strategic masterminds.”

New Pics of General Qassem Suleimani in Tikrit frontline

The New York Times notes that pro-militia websites "circulated photographs of General Suleimani on Wednesday drinking tea on what was said to be the front line, dressed in black and holding his glass in one hand and a floral patterned saucer in the other."

New Pics of General Qassem Suleimani in Tikrit frontline: Business Insider