A suicide truck bomber targeted a police checkpoint in southern Baghdad on Wednesday night, killing 17 people and wounding at least 60 others.

The bomber detonated the vehicle - an oil tanker laden with explosives, security and hospital officials said, speaking on condition of anonymity under regulations.

Three policemen were among the dead, while the rest were civilians, and a number of police were also wounded, the officials said.

No one immediately claimed responsibility for the attack, but the Islamic State of Iraq and the Levant (ISIL) group has carried out similar attacks in the past.

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Iraqi forces are fighting ISIL in western Mosul, where some 2,000 fighters are launching fierce counter-attacks. After launching the operation to retake Mosul in October, Iraqi authorities in January declared they had recaptured eastern Mosul, which is separated from the city's western neighbourhoods by the Tigris River.

Iraqi special forces and police fought ISIL to edge closer to the al-Nuri mosque in western Mosul on Wednesday, tightening their control around the landmark site.

The close-quarters fighting is focused on the Old City surrounding the mosque, where ISIL leader Abu Bakr al-Baghdadi proclaimed a caliphate nearly three years ago across territory controlled by the group in both Iraq and Syria.

Thousands of residents have fled from ISIL-held areas inside Mosul, the fighters' biggest remaining stronghold in Iraq. But tens of thousands more are still trapped inside homes, caught in the fighting, shelling and air strikes.

Western Mosul is densely populated and has proven to be a much more difficult fight for Iraqi and coalition forces, which have resorted to greater use of artillery and air strikes to clear and hold territory.

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A number of air raids have resulted in high civilian casualties. The US-led coalition says a strike in western Mosul on March 17 probably resulted in mass civilian casualties and is investigating the incident.

Iraqi witnesses have said air strikes earlier this month killed scores of civilians - with some estimates as high as 400 dead.

Local officials and witnesses say as many as 240 people may have been killed in the al-Jadida district when a huge blast caused a building to collapse, burying families inside. Rescue workers are still pulling bodies out of the site.

One local health official said on Wednesday that 250 bodies had been recovered from the site, though that is higher than Iraqi military estimates.