The military undertook a two-day offensive backed by helicopters, sweeping militant positions in Salahudin, Kirkuk and Diyala provinces, an official from Salahudin Operation Command told Chinese news agency Xinhua.
Fourteen militants were killed, and 16 arrested, and troops seized 10 booby-trapped cars, and caches of weapons and explosives.
The operation was based on intelligence reports that said that militants planned to seize Tikrit to divert army resources from militants in the western province of Anbar, the source said.
Meanwhile, four soldiers were killed and one injured when gunmen opened fire on a checkpoint near the city of Kirkuk, police said.
Five people died and three were injured by gunmen in the eastern province of Diyala.
A car bomb in Baquba injured two people.