Angry Shiites marched Wednesday and set fire to the offices of a secular politician after a Sunni Arab guest criticized Iraq's Shiite religious leaders during an Al-Jazeera talk show.

The station's Baghdad correspondent also resigned in protest of the remarks by Fadel al-Rubaei, a Sunni politician living in exile. Al-Rubaei said Shiite clerics should not take part in politics, and he accused them of conspiring with the Americans against the mostly Sunni insurgents.

The statements angered many Shiites, including many who did not see the Al-Jazeera broadcast but saw reports of it on an Iraqi station, Al-Furat, owned by the biggest Iraqi Shiite party.

Al-Furat said legislator Abdul-Aziz al-Hakim, head of the Supreme Council for the Islamic Revolution in Iraq, "condemns violations against Shiites' religious leaders broadcast through one of satellite channels known for its hatred to the Iraqi people."

Officials at the Qatar-based Al-Jazeera were not available for comment. But Baghdad correspondent Atwar Bahjat told The Associated Press that she resigned from her job "in protest of what the guest of the station said."

Al-Rubaei made his comments during the "Opposite Direction" program shown Tuesday night and Wednesday afternoon on Al-Jazeera.

"Clerics, especially those in the Shiite seminary, go to your mosques and don't work in politics. Keep politics for politicians and stop conspiring against the resistance," he said.

Hours later, thousands of people chanted anti-Al-Jazeera slogans in the streets of the Baghdad neighborhoods of Sadr City and Karradah, and in the southern cities of Najaf and Karbala.

The demonstrations, which turned into political rallies, threatened to further polarize Thursday's parliamentary elections after angry Shiites in the southern city of Nasiriyah set fire to a building housing the offices of former interim Prime Minister Ayad Allawi. Allawi, a secular Shiite, has campaigned on a platform calling for national reconciliation.

"The headquarters was attacked by militiamen who broke inside and set fire to the building. This is a terrorist act that contradicts democracy and this is the reason we are calling for eliminating the militia groups in Iraq," Allawi spokesman Thaer al-Naqib told The Associated Press.

Several Shiite groups still maintain armed militias.

"Those militiamen consider the political process as a threat to them and they want to stop this process. Those militia groups are working against the hopes of the Iraqi people and they should be finished," al-Naqib said.

The Shiite United Iraqi Alliance, which holds most of the seats in parliament, is expected to do well in Thursday's elections. Shiite spiritual leaders have indirectly asked their followers to vote for the slate.

Al-Rubaei said the Shiite clerics were "the biggest conspirators against the resistance. They are the ones who want it to die in its first confrontation with the Americans."

A group of senior religious students in the Shiite holy city in Najaf, where the country's top four Shiite clerics live, called the program "a provocation and flagrant aggression on the values and feelings of Muslims whether in Iraq or around the world."

The statement said Al-Jazeera "is financed by countries, governments, regimes, intelligence agencies and Muslim extremists who came to power through military coups."

The students said people will respond to Al-Jazeera at the polls Thursday. They added that Al-Jazeera knows that the emir of Qatar came to power in a military coup against his father.