Iraqi police say gunmen have killed 13 soldiers on an army base in the country’s northeast, bringing the nationwide death toll to 82 in the single bloodiest day so far this year.

Two senior police officials said the gunmen arrived at dawn on Monday at the military base in the town of Udaim in three vehicles and began shooting at soldiers. No others were wounded.The attack was one in a wave of violence across the country that left 82 dead.

The police spoke on condition of anonymity because they were not authorized to speak to the media.It was the single deadliest day in Iraq since the US military left last December.

At least 29 people were killed and 75 injured in more than 12 bombings and attacks in central and northern Iraq on Monday.The wave of attacks came after the start of the Islamic holy month of Ramadan.

Meanwhile, six people were killed and 32 injured in a series of car bombs and attacks in Baquba city, 60 kilometres northeast of Baghdad.

A car parked near a medical centre in Khan bani Saad area exploded, followed by another in al-Mohandesin area in the centre of the city, a police official said.

Two soldiers were among those killed.

Eight car bombs exploded in the northern city of Kirkuk, killing eight and injuring 35.

In the capital, a roadside bomb injured five people when it went off in a residential Baghdad neighbourhood.

Monday’s attacks follow a series of bombings that shook Iraq on Sunday evening, killing at least nine people.

Violence in Iraq has dropped dramatically in recent years, but near-daily attacks still take place amid a political stalemate in the country stemming from feuds between Shiite and Sunni politicians.

Insurgents usually escalate their attacks during Ramadan. Last year, al-Qaeda vowed to launch 100 attacks during the holy month to avenge the death of its former leader Osama bin Laden, during which dozens were killed. And the attack comes days after the leader of al-Qaeda in Iraq warned that the militant group is regrouping.