Militants killed 12 people in a shooting and a suicide bombing Saturday in the northern Iraqi city of Tikrit, which was recaptured from ISIS last year, police said.

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

Militants shot dead four security personnel 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.

An unverified photograph shared on social media showed two dark plumes of smoke rising into the sky near arches at the city’s northern gates.

After the attacks, police tightened security in Tikrit, which already had some of the most restrictive security measures in place following its recapture from ISIS. It was not clear if other assailants were still in the area.

There was no immediate claim of responsibility for the attacks, but ISIS frequently carries out suicide attacks targeting both civilians and security forces in Iraq.

Hometown of executed dictator Saddam Hussein, Tikrit lies 160 kilometers north of Baghdad and was the second city to fall to ISIS in 2014 as the jihadists 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, a city north of Tikrit that is the last one held by the terrorist organization in the country.

Western officials have indicated that the drive for Mosul, Iraq’s second city, may begin next month, though Baghdad has declined to specify when it will start.