It was the second time in two days that protesters were fired on, as a crowd attacked the headquarters of the Patriotic Democratic Party of Kurdistan headed by the Kurdish region's President Massoud Barzani, The New York Times reported.
Private security guards fired warning shots in the air but opened fire on the crowd when protesters persisted in throwing rocks at the building, the newspaper reported. Initial reports said at least five people had been killed, but a health official later said there was only one confirmed death.
On Wednesday, the governor of a southern Iraqi province fled when protesters stormed his headquarters during demonstrations in which three people died, officials said.
Violence erupted after local police fired on demonstrators protesting poor service and corruption outside government buildings in Kut in Wasit province, killing three and wounding more than 50, The Washington Post reported.
The protesters set fire to several government buildings, officials said.
Capt. Mahdi Abbas of the province's emergency police force said the governor escaped through a back door with his body guards. Other members of the provincial council also fled, and the Iraqi army was called in to subdue the turmoil.
Reached by telephone at police headquarters in Kut, where he took refuge, Gov. Latif Hamad al-Turfa blamed the turmoil on "thugs and gangs," the Post said.
On Thursday about 1,000 protesters took to the streets demanding the release of 45 people arrested in the Kut protests.
Iraqi Prime Minister Nouri al-Maliki declared curfew in Wasit indefinitely and promised an investigation.
"This is very, very dangerous," political analyst Ibrahim Sumaiedi told the Post. "Society is divided along ethnic and sectarian lines, and everyone is armed. If this happens in other cities in Iraq, we will face not reform or change but something far more devastating, because there are a lot of weapons in Iraq."
Local officials also reported unrest in Afak in Diwaniyah province, where demonstrators rushed a building housing the City Council and set it on fire.
Kadhim Saiyadi, a Kut lawmaker aligned with Shiite Muslim cleric Moqtada Sadr's movement, said the protesters split into three groups and attacked three sites, the Los Angeles Times reported.
He blamed the arson on government infiltrators who want to prevent the demonstrations from becoming a full-blown popular uprising.
"I think the infiltrators wanted to destroy the demonstrations inside Iraq to have a pretext not to permit any demonstrations in future," he said.