A spate of suicide bombings against security forces were the deadliest in attacks that killed 16 people Tuesday as Iraq announced more executions amid a protracted pre-election surge in violence.

The bloodshed, which has killed nearly 6,000 people so far this year, has fuelled fears Iraq is slipping back into the brutal sectarian war of 2006-07, and has spurred officials to appeal for international help in combatting militancy.

Baghdad has also voiced concern over a resurgent Al-Qaeda emboldened by the civil war raging in neighbouring Syria, and the government has trumpeted long-running operations against militants that officials say are having an impact.

But that has done little to quell a spate of deadly attacks, with violence hitting primarily Sunni Arab areas of the country that have borne the brunt of recent unrest.

Tuesday's deadliest attack hit an army base in Tarmiyah, just north of Baghdad, killing at least seven soldiers and wounding 22 others, according to a police colonel and a health official, speaking on condition of anonymity.

A police officer in the town said the attack began with mortar fire raining down on the base, spurring soldiers to leave the facility via the main gate to investigate who set them off.

At that point the suicide bomber blew himself up, and the explosion was followed by a firefight between militants and soldiers, the officer said.

Iraqi troops based in Tarmiyah have been targeted by militants on multiple occasions.

On November 7, two successive car bombs set off by suicide attackers at another nearby military installation killed 16 people and wounded dozens more.

Two suicide bombers also attacked a police station in Taji, another town just north of Baghdad. One of the attackers was shot dead, but the second manged to blow himself up, killing four policemen and wounding nine others.

Attacks in Baghdad, Fallujah, Mosul, and Kirkuk left five more people dead while security forces in the southern port city of Basra also found the dead bodies of two tribal chiefs who had been kidnapped in southern Iraq recently.

The violence came on the same day authorities announced the execution of 11 convicted "terrorists", bringing to at least 162 the total number of those put to death so far this year, according to an AFP tally based on the justice ministry and officials.

A post uploaded to the ministry's Facebook page, confirmed as authentic by a ministry official, listed the men by their initials along with the crimes they were convicted of having committed.

Executions in Iraq, usually carried out by hanging, have increased this year compared with the 129 carried out last year despite persistent international calls for a moratorium.

Diplomats have voiced worry that the pace of executions in Iraq may increase ahead of elections due to be held on April 30, arguing that officials will be keen to show they are tough on security.

The United Nations, European Union and human rights groups have condemned the high rate of executions, with UN human rights chief Navi Pillay saying earlier this year that Iraq's criminal justice system was "not functioning adequately".

But Iraqi Justice Minister Hassan al-Shammari has insisted the executions are carried out only after an exhaustive legal process.

The growing use of the death penalty comes as violence in Iraq has reached a level not seen since 2008, when the country was just emerging from a brutal sectarian conflict.

Diplomats, analysts and rights groups say the government is not doing enough to address the root causes of the unrest, particularly disquiet among Sunnis over alleged mistreatment at the hands of the Shiite-led authorities.

Prime Minister Nuri al-Maliki used a recent trip to Washington to push for greater intelligence sharing and the timely delivery of new weapons systems in a bid to combat militants.

French Ambassador to Iraq Denys Gauer on Monday offered weapons, training and intelligence cooperation.