MARRA: Militants killed 12 people in a shooting and a suicide bombing Saturday in the northern city of Tikrit, which was recaptured from the Islamic State group last year, police said.

Tikrit was seized by IS in June 2014, but the city has largely been spared attacks that have plagued other parts of the country since its recapture.

Militants shot dead four police at a checkpoint on the west side of the city, then continued north and detonated an explosives-rigged vehicle at another checkpoint, killing eight more people, a police colonel and lieutenant colonel said.

The attacks also wounded a total of 23 people, according to the officers.

Tikrit, located 160 kilometres north of Baghdad, was the second city to fall to IS in 2014 as the militants swept through large areas north and west of the capital.

It was also the first city to be recaptured by Iraqi forces, which are now preparing for a push on Mosul, the last IS-held city in the country.