Air strikes on the city by the Iraqi air force resumed on Tuesday as the sky cleared after several days of bad weather, the Iraqi military said.
The improved weather should also allow ground forces to resume their advance toward the Grand al-Nuri Mosque, where Baghdadi, declared a "caliphate" almost three years ago over parts of Iraq and Syria. Since then, IS militants have launched a number of big attacks in and around Tikrit, located about 80 miles (130 kilometers) north of Baghdad. He said there were around 10 attackers, including two suicide bombers. The assailants blew themselves up when they ran out of ammunition, it said.
The Ministry of Defense says in a statement that the incident happened during the operation to retake the city from IS militants.
The attacks targeted a police checkpoint and the house of a police colonel, who was killed with four members of his family, officers said. The two other strikes killed militants and destroyed weapons and vehicles.
Five militants are thought to be hiding and Mahmoud said Tikrit authorities had declared a curfew on Wednesday.
Iraqi forces are battling to recapture west Mosul from IS, killing and wounding hundreds of civilians and pushing more than 200,000 to leave their homes.
The insurgents are putting up stiff resistance in the remaining district under their control in northwestern Mosul and the densely populated Old City.
The government has encouraged residents not to flee during the fighting - a policy aimed at easing ease the burden of widespread displacement but which can heighten the risk of injury or death for civilians.
The helicopter was providing air support to Federal Police forces battling Islamic State fighters on the western side of Mosul, the statement said.
The Iraqi air force is conducting strikes against ISIS in Mosul in coordination with the USA -led coalition air forces.