At least 12 members of the Iraqi security forces have been killed in a suicide bomb attack on the former US base of Camp Speicher, outside Tikrit.
There were reports of about five bombers at the camp's western gates. So-called Islamic State (IS) said it carried out the attack. Most of the dead were police recruits.
The attack comes as IS continue to counterattack on the edges of the city of Ramadi, a week after it was recaptured by Iraqi troops. The BBC's Thomas Fessy, who has just returned from Ramadi, the capital of Anbar province, says there has been heavy fighting in the centre and north-eastern districts of the city, and the Iraqi forces have been taking casualties.
The Iraqi government said a week ago that it had "liberated" Ramadi from IS. The jihadist group had held the city since May. The attack on Camp Speicher took place in early hours of Sunday morning. At least 20 police were also injured.
They are reported to be police from Nineveh province, training to take it back from IS. IS said in a statement that it had carried out the attack, adding that it had targeted "trainers from the rejectionist army", referring to Shia Muslims, Reuters news agency reported.
Camp Speicher was the scene of a massacre by IS of up to 1,700 Iraqi Shia troops during their advance across the region in June 2014, some of which has been reversed. Iraq's Defence Ministry says IS has stepped up suicide attacks since it lost control of Ramadi.