Foreign ministry spokesperson Syed Akbaruddin declined to say who had taken the nurses, or where they were headed, but said the government had spoken with them shortly before they boarded the bus.
Asked about reports of an explosion near the hospital, he said was not aware of a blast, but that some nurses had been lightly injured by broken glass.
“In zones of conflict there is no free will,” Akbaruddin told reporters at a briefing, when asked if the nurses had been kidnapped.
“This is a situation where lives are at stake.”
Tikrit, the birthplace of former President Saddam Hussein, has been the site of fierce fighting this week as Iraqi troops battle to regain control of the city from al Qaeda splinter group the Islamic State in Iraq and the Levant (ISIL).