Two suicide bombing attacks claimed by the Islamic State group rocked Tikrit and Samarra, two Iraqi cities north of Baghdad.

A booby-trapped ambulance, driven into Tikrit’s southern checkpoint, killed at least 15 people and wounded 33-- blowing some victims into a nearby river. In Samarra, (south of Tikrit) an ambulance was driven to a car park for the al-Askari mosque, a holy shrine of Shia Islam, adding Iranian pilgrims to the death toll.

These deadly Sunday attacks are the latest since the Iraqi government pushed an offensive into Mosul on Friday, special forces securing a position in the eastern districts of the city.

Mosul is the last ISIS-controlled city in Iraq. It fell to jihadists in 2014 and the government’s push into the region marks the first time the Iraqi Army has entered Mosul since then. The self-declared caliph of the Islamic State, Abu Bakr al-Baghdadi, still lives in Mosul according to Kurdish officials.

Government forces expect the push to be successful, with attacks on the eastern front supported by coordinated with US-led airstrikes.