Dozens killed in IS blasts targeting Iraqi Shia pilgrims

In Tikrit, a suicide bomber rammed an explosive-laden ambulance into the provincial capital's main checkpoint at the southern entrance during a morning rush hour, killing 13 people.

Another attacker detonated his vehicle - which a local operation command said was also an ambulance - in a car park for pilgrims visiting the Shia site of al-Askari mosque in Samarra, south of Tikrit.

"In total, 21 people were killed and 22 others injured, most of them Iranian pilgrims," a local source told The New Arab, adding that the death toll was likely to rise.

"Iraqi security forces and local militias have been deployed across the city and a curfew has been imposed in fear of other possible attacks," the source said.

The Islamic State group claimed responsibility for the attacks in a statement released by IS-affiliate news agency Amaq.

The attacks come as Iraqi forces engage in an offensive in northern Iraq to retake Mosul, the last IS-held city in the country, after regaining much of the territory the extremists seized in 2014 and 2015.

IS has launched a series of diversionary attacks since the start of the Mosul operation on 17 October in a bid to draw both attention and forces away from the battle.

But even the recapture of Mosul will not mark the end of the war against IS, which still holds other territory in Iraq and is likely to turn increasingly to insurgent tactics such as bombings and hit-and-run attacks as it loses more ground.