Interior Minister Suleyman Soylu said 27 of those killed were police and two were civilians.
Turkey declared a one-day morning on Sunday after twin blasts ripped through the heart of Istanbul following a football match killing 29 people, mainly police, and wounding 166, the state-run Anadolu news agency said.
Prime Minister Binali Yildirim also ordered flags to fly at half mast after a car bombing near a football stadium followed by a suicide bombing at a nearby park, Anadolu said.
Interior Minister Suleyman Soylu said 27 of those killed were police and two were civilians, adding that 10 suspects had already been detained.
No group has claimed the blasts which were the latest in a year that has seen Istanbul and other Turkish cities rocked by a string of attacks blamed on ISIS terrorists and Kurdish extremists.