For weeks, Sunni Arab tribesmen have taken over the centre of a city north of Baghdad, all with one goal -- to rail against the "injustices" of Iraq's Shiite-led authorities.

Although protests against Prime Minister Nuri al-Maliki and his Shiite-led government have gripped Iraq since December 23, demonstrations in Samarra and surrounding Salaheddin province began relatively late.

But from January 1, the tribes of Samarra, whose influence is considerable, took over Al-Haq Square (Square of the Righteous) and invested in infrastructure that means their rallies now show no sign of petering out.

"We were novices in the art of demonstrating," admitted Naji Abbas al-Mizan, a spokesman for the demonstrators.

Thousands - exclusively men - brave the January cold and huddle together over cups of bitter coffee as loudspeakers blare songs glorifying Iraq that date back to the rule of now-executed dictator Saddam Hussein.

They sleep in tents surrounding a large platform from where speeches are delivered. During the day, children wander around the square as Iraqi flags, including at least one flown during Saddam's rule, flutter in the wind.

The day is marked by the call to prayer at the nearby Al-Razzaq mosque, and the regular arrival of trucks of food. In the evening, microphones are handed to protesters who angrily criticise Maliki for having "insulted" them.

"The government in Baghdad should not exclude us or marginalise us," said Talal Khaled al-Sawi, a tribal leader. "We are denied jobs, we are denied our rights. The government does not investigate when our loved ones disappear, and it wants us to remain silent?"

Haitham al-Haddad, head of the Ashraf tribe in Samarra, said the rallies were being driven by the province's powerful tribes.

"All the tribes of Samarra are participating (in the protests)," said Haddad, wearing a traditional red and white chequered headscarf. "There are 25 tribes from Samarra, and 10 to 15 of their allied tribes."

Iraq's Sunni Arab minority has demonstrated in large numbers since late December, with protests sparked at first by the arrest of at least nine guards of Sunni Finance Minister Rafa al-Essawi on terror charges.

They have decried the alleged wrongful arrest of members of their community and claimed the Shiite-led authorities misuse anti-terror laws to target Sunnis.

As time has gone on, their anger has focused on Maliki.

"Maliki has militias!" shouted Ahmed Haza, a young demonstrator who said he had suspended his studies in Ukraine to "stand beside my brothers ... (and) fight against injustice".

"He (Maliki) kills people, he has small armies at his disposal," Haza said. "He has to go!"

Maliki has responded with a carrot and stick approach. He has alternated offers of concessions and threats to direct the security forces to break up the protests -- in particular one rally in Anbar province that has blocked the main highway linking Baghdad to Syria and Jordan for more than three weeks.

Most recently, however, the government released 335 detainees and a top minister apologised for wrongfully holding inmates without charge.

Despite the conciliatory overtures, the rallies at Al-Haq square show little sign of abating, and continue to voice anger over maltreatment of the Sunni Arab minority.

Tribal leaders voiced frustration that their community remains a target of kidnappings and bombings. These occur far more frequently in Sunni areas, and in particular Salaheddin, than in the rest of Iraq.

Protesters and tribal leaders were keen to avoid enflaming sectarian tensions, with memories still fresh of Iraq's brutal communal bloodshed of recent years.

But while powerful Shiite cleric Moqtada al-Sadr has forecast an "Iraqi spring" and publicly voiced support for the Sunni demonstrations, rallies in Shiite-majority areas have backed the premier.

"We call on our Shiite brothers in the south to protest, because we are all one people and we want to preserve national unity," said Abu Tareq, a 51-year-old retiree.

"We are all united by blood, and by the ties of Islam."