BAGHDAD: Shiite cleric Muqtada al-Sadr reached out to Iraq's religious minorities Friday, visiting a Baghdad church desecrated in a deadly 2010 attack as well as a prominent Sunni mosque as public opposition spread against his rival, Prime Minister Nouri al-Maliki.

The anti-U.S. cleric's stops at the holy sites - a rare public appearance by al-Sadr outside predominantly Shiite parts of Iraq - came as tens of thousands of primarily Sunni protesters angry over perceived second-class treatment rallied to maintain

pressure against al-Maliki's Shiite-led government.

Friday's demonstrations reached well beyond the desert province of Anbar that has been the hub of two weeks of unrest, touching a string of Sunni-dominated communities in Iraq's north and west. Cries of "Down, down with al-Maliki" echoed in the streets of the northern city of Mosul, while protesters in the capital Baghdad accused the prime minister of being a liar.

The government has tried to appease the demonstrators by agreeing this week to release some detainees, bowing at least in part to one of their more emotionally charged demands. But that gesture has done little to stem their rage.

In a statement Friday, the prime minister urged government security forces to show restraint toward protesters. He also called on demonstrators to avoid acts of civil disobedience and warned them that "foreign agendas" seek to push Iraq toward sectarian conflict again.

Al-Sadr, who has voiced support for the protesters, appears to be trying to capitalize on the political turmoil by attempting to portray himself as a unifying figure ahead of provincial elections in the spring. He spoke up for the Sunni protesters' right to demonstrate earlier this week, and echoed that sentiment again Friday.

"We support the demands of the people, but I urge them to safeguard Iraq's unity," he said.

Wearing his signature black cloak and turban, the cleric said he visited the Our Lady of Salvation church to express sorrow at the attack and send a message of peace to Iraq's dwindling Christian community, which is estimated to number about 400,000 to 600,000.

He sat quietly in the front pew, listening and nodding as Father Ayssar al-Yas described recent renovations to the church. The priest then led al-Sadr on a tour, pointing out places where attackers in 2010 killed priests and worshippers in an ambush during Mass. More than 50 died in the attack, blamed on Sunni extremists.

Al-Maliki himself attended a ceremony to officially reopen the church last month.

Al-Sadr's visit took place at a time of rising sectarian tensions a year after the U.S. withdrawal from Iraq. Al-Sadr grudgingly backed fellow Shiite al-Maliki following elections in 2010. But last year he joined Iraq's minority Sunni Arabs and Kurds in calling for al-Maliki to resign.

Al-Sadr rose to prominence as the leader of a militia movement that battled American forces following the 2003 U.S.-led invasion, and he has in recent years made overtures to Sunnis and others. But fighters loyal to him were among the worst perpetrators of sectarian violence last decade, and he is still viewed with hostility or suspicion by many Iraqis.

After visiting the church, al-Sadr's heavily protected convoy made its way to the Abdul-Qadir al-Gailani mosque, one of Baghdad's most prominent Sunni places of worship, shortly before midday Friday prayers.

As he entered the mosque, one worshipper called out that he is "the unifier of Sunnis and Shiites." Another hailed him as "the patriot, the patriot." Women in the courtyard ululated and showered him with candy on the way out.

Protesters, meanwhile, massed in several Sunni areas around the country.

The demonstrations appeared to be some of the largest in a wave of rallies over the past two weeks that erupted following the arrest of bodyguards assigned to Finance Minister Rafia al-Issawi, one of the central government's most senior Sunni officials.

The detention of female prisoners has been a focus of the demonstrations, though the protests tap into deeper Sunni feelings of perceived discrimination and unfair application of laws against their sect by al-Maliki's government.

Iraqi authorities this week ordered the release of 11 women facing criminal charges and pledged to transfer other women prisoners to jails in their home provinces in a nod to protesters' demands.

But demonstrators Friday continued to press for more prisoners to be released.

Several thousand people rallied amid tight security in the courtyard of Baghdad's Abu Hanifa mosque after midday prayers. They demanded the release of detainees, and held banners with slogans against the perceived politicization of the judiciary. They also called for an end to corruption.

Their chants included: "Iran out!" - a reference to what many Iraqis see as their neighbor's influence over the government - and "Nouri al-Maliki is a liar."

Local TV broadcast what appeared to be tens of thousands of protesters massed along a highway near the western city of Ramadi, which has been the focus of demonstrations and sit-ins in recent weeks. Large crowds also converged on a stretch of the same highway near Fallujah.

About 3,000 people gathered in the northern city of Mosul, where they called for the release of female prisoners and to end to what they say are random arrests of Sunnis. Among their chants were: "Down, down with al-Maliki" and "No to sectarianism."

In the ethnically mixed city of Kirkuk, about 1,000 protested to demand the release of Sunni detainees.

Protests were also reported in other areas, including the Sunni stronghold of Tikrit, the hometown of former dictator Saddam Hussein.