An ISIS booby-trapping expert died alongside three helpers after a car he was rigging with bombs exploded in his workshop.

Abu Yusuf al-Halab, a Syrian in his forties, was killed in the blast near the town of Tal Afar, reports an Iraq-based news agency.

The man was known as 'al-mohandis', Arabic for engineer, according to a source who asked to remain anonymous.

Abu Yusuf al-Halab, a Syrian in his forties, was killed in the blast near the town of Tal Afar, according to an Iraq-based news agency. Pictured: ISIS fighters parade through Raqqa

The source told AlSumaria News: 'Abu Yusuf al-Halabi, a prominent expert of vehicles booby-trapping in Tal Afar, was killed along with three of his aides.

'This was due to an explosion of a car while booby-trapping it inside a workshop.'

The incident follows the death of an ISIS commander by sniper fire around the same location.

Tal Afar remains an important ISIS stronghold, and is being targeted by the Iraqi state-backed Hashed al-Shaabi militia.

The force recently took Hatra, 80 miles southwest of Mosul, and recapturing Tal Afar is seen as the next step in their campaign.

The ancient city is one of the heritage jewels of Iraq and was damaged by IS after they took over large parts of the country three years ago.

Tal Afar remains an important ISIS stronghold, and is being targeted by the Iraqi state-backed Hashed al-Shaabi militia

They recently took Hatra, 80 miles southwest of Mosul, and recapturing Tal Afar is seen as the next step in their campaign

Meanwhile, fighting continues to retake Mosul, Iraq's second city and ISIS' last major urban stronghold in Iraq.

According to the UN, more than half a million civilians have been forced to flee their homes since the offensive was launched more than six months ago.

Iraqi forces have made steady progress in west Mosul but the jihadists are expected to make a bloody last stand in the narrow streets of the Old City.

An estimated 400,000 civilians remain trapped in the Old City, making it difficult for Iraqi or US-led coalition aircraft to provide ground troops with air support.