The blast in Sulaimaniyah occurred Thursday evening and left at least 11 dead and 13 injured, the city's emergency response chief Saman Nader told AFP.

He blamed the blast on "a gas leak from a tank".

Much of war-ravaged Iraq's infrastructure is dilapidated and tragedies are common. The country also suffers from poorly enforced safety standards, particularly in the transport and construction sectors.

Nader said four people had still not been freed from under the rubble of the collapsed three-storey house, in the second largest city of Iraq's autonomous Kurdistan region.

"Our teams have been working for more than 15 hours to rescue the people trapped under the collapsed house," Nader said.

Local residents watched on Friday morning as emergency workers, assisted by a backhoe, continued the rescue effort among collapsed white bricks and twisted metal.

The explosion shattered the windows and blackened the facade of a neighbouring building.

An earlier toll issued Friday morning by Sulaimaniyah's health authorities had reported 10 deaths.

At least one child is among the victims, according to Sulaimaniyah Governor Haval Abu Bakr, who declared a day of mourning.

At the end of October, at least nine people were killed and 13 others injured when a tanker transporting gas accidentally exploded in Baghdad, the Iraqi capital.

In April 2021, more than 80 people died in a Baghdad hospital fire when improperly stored oxygen cylinders exploded.