At least 12 people were killed and dozens injured in militant attacks in northern Iraq early Saturday, according to a local police officer. 

ISIL militants attacked a security checkpoint in Beji, 40 kilometers north of Tikrit city, Ghazwan al-Jabouri told Anadolu Agency. 

“Four policemen and one militant were killed in ensuing clashes at the checkpoint,” he said. 

Militants also blew up a truck laden with explosives at another police checkpoint north of Tirkit, killing eight people. 

“Nearly 23 police personnel were injured in the assault,” al-Jabouri said. 

Iraqi security forces have imposed a curfew in Tikrit following the attacks. 

Iraq has suffered a devastating security vacuum since mid-2014, when ISIL captured the northern city of Mosul and overran large swathes of territory in the northern and western parts of the country. 

In recent months, the Iraqi army -- backed by coalition airstrikes and local allies on the ground -- has managed to retake much territory from ISIL. 

Iraqi forces this week captured the Shirqat district, 100km north of Tirkit, from ISIL militants ahead of an anticipated offensive to retake Mosul, which Iraqi officials have vowed to recapture by year’s end.