At least 22 people were killed and dozens more wounded yesterday by a truck bomb at lunchtime in a town south of the oil-rich city of Kirkuk, the bloodiest attack to hit Iraq in a month.

The attack struck near a mosque in Taza, a predominantly Turkmen Shiite town, at around noon and claimed women and children among its victims, officials said.

"I saw a truck passing through a very narrow road and, a few minutes later, I heard a huge explosion and the ceiling of my shop collapsed on my head," said Akbar Zain al-Abdin, 40, whose fertilizer and farm products store was almost completely destroyed.

"I didn't see a fire, but I saw a huge cloud of sand in the sky," he said.

"The victims were our relatives and our friends, their houses collapsed on them."

Kirkuk hospital morgue chief Ibrahim Mahmoud and Iraqi police Major Salam Zangana said 22 people were killed in the attack, while Zangana added that 125 were wounded, many of them seriously.

A senior police official, who did not want to be identified, put the toll at 30 dead and more than 125 wounded, and added that the attack was carried out by a suicide bomber and appeared to have been an Al-Qaeda bombing.

The official added that more than one tonne of explosives had been used in the bombing.

"The bombing is a big disaster, the criminals and killers chose this time to attack because it is when farmers return home to their houses for lunch," Majeed Azzat, a member of Kirkuk's provincial council, said.

The Turkmen Front, Iraq's main Turkmen political party, announced three days of mourning and called for an "immediate investigation... and for the criminals to be brought to justice".

The attack, which took place around 400 metres from the Shiite Al-Rasoul mosque, also seriously damaged dozens of houses, with police saying that many victims could still be under the rubble.

An AFP reporter at the scene said the bomb left a deep crater in the ground.

In the aftermath of the attack, police called on local residents to donate blood at nearby hospitals.

It is the bloodiest attack in Iraq since May 20, when a car bomb tore through a Baghdad street full of diners, killing 40 people and wounding 83.

More recently, a car bomb on June 10 in a market in Batha, in the largely peaceful southern province of Dhi Qar, killed 19 people and left 56 injured. The attack was blamed on Al-Qaeda.