BAGHDAD — A populist Shiite leader in Iraq, Muqtada al-Sadr, expressed support on Tuesday for fresh protests against Prime Minister Nouri al-Maliki, a fellow Shiite but his political opponent, saying that al-Maliki bears "full responsibility" for the unrest in the country.

Al-Sadr spoke in Najaf, one of the holiest cities of his Shiite sect, just as Iraq ended its bloodiest year since 2009, a reflection of unabated ethnic, sectarian and political tensions among the country's Kurdish, Arab, Sunni and Shiite populations.

Several times during the gathering, al-Sadr directed his remarks at al-Maliki, who has taken recent steps that suggested he was asserting greater control over many aspects of the government. That has prompted fears he was cracking down on his political opponents.

Al-Sadr's remarks could indicate that he is trying to test the political waters or possible support from the street before Iraq's provincial elections in the spring.

Al-Sadr also tried to assert broader credibility for the anti-al-Maliki protests by comparing them to the movements that have swept many Arab countries in the past few years, calling for new government leaders and better representation.

"The Iraqi spring is coming," al-Sadr said, in a tone that implied a warning to al-Maliki.

"We are with the demonstrators, and Parliament must be with them, not against them," he said. "The legitimate demands of the demonstrators, by which people know what they want, should be met."

Al-Sadr said he supported the widespread demonstrations as long as they were peaceful and did not seek to create divisions, driving the last point home by adding that he was willing to go to Sunni-dominated Anbar province to take part in protests.

Demonstrations against al-Maliki's Shiite-dominated government erupted in Sunni areas last month in response to a raid by security forces on the office and home of the Sunni finance minister, Rafia al-Issawi. In one protest last week, tens of thousands of Sunni Muslims blocked Iraq's main trade route to neighboring Syria and Jordan, Reuters reported.

Tensions between the Kurds in the north and the government in Baghdad, who were already at odds over sharing oil revenues, have risen as soldiers squared off with Kurdish militias after al-Maliki sought to consolidate his control in some parts of the north.

The discord has translated into bloodshed. Iraq Body Count, a nonprofit group that tallies casualties, said Tuesday that civilian deaths from attacks in Iraq rose to at least 4,471 in 2012 from 4,136 in 2011, the first annual rise since 2009. Deaths during the final two weeks were still being tallied.