At least 25 people have been killed in the latest suicide bombings to strike Iraq.
In Samarra, about 70 miles north of Baghdad, at least 11 Shia pilgrims were killed when a bomb blew up an ambulance in the car park of a religious shrine on Sunday.
Ali al-Hamdani, spokesman for the Salahuddin province, said the bomber walked into the crowd of people before detonating the vehicle and blowing himself up.
Five female students are believed to be among the dead and more than 100 people have been injured.
Meanwhile, in Tikrit in the northwest, annother ambulance was detonated at the entrance to the city during the morning rush hour, killing a further 13 people.
Isis has claimed responsibility for the attacks in retaliation for their loss of territory in the north of the country.
The jihadist group identified two of the bombers as "Al-Moslawi" – a nom de guerre that would indicate they were from Mosul, though it could be a propaganda attempt to link militants from other areas with the ongoing battle for Iraq's second city.
The Iraqi Army and Kurdish fighters are currently locked in a battle with Isis to regain control of Mosul – the jihadi group's last major stronghold in the country.
Iraqi forces entered the city on Thursday for the first time in two years, but fighting remains intense and there are fears the terrorists could destroy the city in their wake.
The World Health Organisation condemned the use of ambulances in the bombings, saying this form of attack made it harder for emergency services to help people in need.
In a statement to The Independent, a spokesman said: "The reported use of medical vehicles as weapons threatens the ability to deliver health care and urgent medical services.
"When ambulances are suspected as potential security threats, their freedom of movement to care for the sick and injured is at risk of life-threatening delays. Such delays will leave vulnerable people with even less access to life-saving medical care.
"WHO is increasingly concerned by the continuous threats to health workers, facilities and transport.
"WHO is working together with national health authorities and partners to protect patients, health workers, health infrastructure and supplies from violence and thus minimise disruptions to desperately needed health care."
Additional reporting by agencies
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