The gathering came after the authorities in Basra cancelled a curfew announced earlier by their counterparts in Baghdad, only minutes before it had been due to take effect.

Security forces deployed massively in the area and encircled the protesters, an AFP correspondent at the scene said, adding there were no incidents.

Elsewhere in the city, calm after days of unrest sparked by anger over poor public services, firefighters were busy all morning trying to extinguish blazes.

They trained their hoses on flames still burning at the provincial headquarters, which protesters have targeted with Molotov cocktails and other incendiary devices.

The massive complex surrounded by concrete walls is seen by the protesters as a symbol of a corrupt leadership that has failed to deliver basic services in the region.

The southern province of Basra is rich in oil and is the only one in Iraq with access to the sea.

"The people protest and the government doesn't care, treats them as vandals," said Ali Saad, a 25-year-old at the rally.

"Nobody (here) is a vandal: the people are fed up, so yes they throw stones and burn tyres because nobody cares," he told AFP near the building littered with debris.

Ahmed Kazem, who was also at the protest, urged the leaders to respond to the demands of the demonstrators "so that the situation doesn't degenerate".

The 42-year-old said these included "public services, water, electricity and jobs" for the people in the region of Iraq with the most oil reserves but worsening infrastructure.