Hundreds of demonstrators rallied in central Baghdad on Saturday to back Prime Minister Nuri al-Maliki, as the latest in weeks of anti-government rallies in Sunni areas of Iraq called for him to quit.

The demonstrations have worsened a political crisis that pits Maliki against his erstwhile government partners, with the premier facing accusations of authoritarianism and sectarianism ahead of key provincial polls.

At Tahrir Square in the heart of the capital, demonstrators held up posters of the prime minister alongside banners that read, "I am Iraqi, I love Maliki," and "We strongly support Nuri al-Maliki."

Many shouted in unison: "All the people support Nuri al-Maliki".

In a sign of increasing sectarian rhetoric at the rallies, many demonstrators held up banners describing themselves as "followers of Hussein," a revered figure in Shiite Islam. A speaker led the crowd in chants of "Labeika Ya Hussein," or "We will follow you, Hussein".

Banners also blamed parliament speaker Osama al-Nujaifi, a Sunni Arab opponent of Maliki, for militant attacks.

Demonstrators said the premier should resist demands for a wide-ranging prisoner amnesty and reform of anti-terror laws, both of which are key demands of anti-government protesters.

"In the names of all the martyrs, the victims, the widows, we call on the government not to cancel Article 4," said one protester, a 67-year-old who gave his name as Abu Hussam, referring to a widely cited article of Iraq's anti-terror law.

Abu Hussam said his son was killed by gunfire in Baghdad in 2006.

"He was 20, I was about to get him married. For six years, I have not slept, I hope one night I can sleep."

Dozens of people also took part in a pro-government rally in the southern port city of Basra, an AFP journalist said.

Meanwhile, anti-government rallies blocked a key highway linking Baghdad to Jordan and Syria for a third week. Protests were also held in Samarra, Tikrit, Baiji and Mosul, all Sunni-majority areas north of the capital.

The demonstrations have decried alleged misuse of anti-terror laws to wrongfully hold members of their community, and claim they are being targeted by the Shiite-led authorities.

In the longest-running of the protests, in western Anbar province, tribal leaders called for Maliki to resign.

"We want Maliki to fall, because he has insulted our dignity many times," said Ali al-Hatem, a leader of the powerful Dulaim tribe. "We will not leave until you find a replacement for Maliki. Then we can negotiate."

In Samarra, imam Abdulrahman al-Samarraie told AFP: "Maliki should leave. We gave him many chances but he did not do anything. He made many promises... but he did not fulfil those promises. He should leave."

The premier has threatened to direct security forces to intervene in the protests, which were sparked by the December 20 arrest of at least nine guards of Sunni Finance Minister Rafa al-Essawi.

Essawi is a leading member of the secular Sunni-backed Iraqiya bloc that, while a member of Maliki's unity government, has called for him to quit.

Powerful Shiite cleric Moqtada al-Sadr, whose movement counts 40 MPs and five ministers among its ranks, has also publicly opposed Maliki.

Saturday's protests come with barely three months to go before provincial elections in April, a key barometer of support for Maliki and his opponents ahead of national polls next year.