BAGHDAD -- -Widespread unrest is engulfing southern Iraq as Iraqis frustrated by shortages of electricity, water and jobs vent their anger, setting fire to political offices, attacking government infrastructure and deepening uncertainty about the country's shaky political future.

The government on Saturday cut off Internet access across much of Iraq and ordered security forces on high alert after demonstrations that erupted six days ago in the southern port city of Basra spread overnight to many other parts of the overwhelmingly Shiite south, where a heat wave has aggravated poor living conditions,

Some of the worst violence took place in the city of Najaf, a destination for Shiite pilgrims from around the world. Protesters stormed the airport and marched on the headquarters of the main Shiite political parties, including the local headquarters of Prime Minister Haider al-Abadi's Dawa Party, which was set on fire.

Thousands of people also attacked government infrastructure and the offices of Shiite parties in the cities of Nasseriyah, Kut, Karbala, Babil and Amara. In Basra, they marched on the hotel where Abadi had stayed during a brief visit aimed at calming the situation. There was one small protest reported in Baghdad early Saturday, with demonstrators setting fire to tires and briefly closing access to the main highway leading to Jordan.

The upheaval comes at a critical time for the Iraqi government, which has been paralyzed since inconclusive and tainted elections in May. The ballots are now being recounted after allegations of fraud, and though the overall results aren't expected to change much, the recount has delayed the seating of a new parliament and the formation of a new government.

This is not the first time that demonstrations, triggered at least initially by the lack of electricity during the hot summer months, have destabilized southern Iraq. Persistent power shortages since the U.S.-led invasion leave people sweltering without fans or air conditioners. This year conditions have been worsened by a severe drought, which has reduced the availability of water, and a decision by Iran to cut off the electricity it exports to Iraq because of a dispute over payments, further reducing the supply.

But these demonstrations seem more widespread and by Friday had taken on a decidedly political and anti-Iranian flavor. The protesters are turning much of their wrath against the Shiite parties that have dominated Iraqi politics since the toppling of Saddam Hussein in 2003, as well as against Iran, which is closely allied to the Shiite political establishment.

Iraqis say they blame the government, including Abadi and many other Shiite politicians, for the failure to provide jobs, infrastructure and improve the economy. Allegations of corruption at all levels of government are widespread, and the close relationship of many of the Shiite elites with Iran has deepened the resentment.

"We've had enough of these parties who put Iranian interests ahead of us and treat the people like wood to burn when they need money," said Abdulrahman Mohammed, 36, who has been participating in the protests in Basra.

"What's happening now is an explosion after years of pressure. We want our rights and we have nothing to lose because they took everything."

In a video showing the attack on the Dawa Party headquarters in Najaf, a protester is heard referring scornfully to the party that has dominated Iraqi politics since 2006 as "the Iranian Dawa Party." In another video, demonstrators can be heard chanting "burn the Iranian parties."

"We want to end these corrupt political parties just like we ended Saddam," said Haidar al-Taie, 24, a medical student in Najaf who was one of those who burned the Dawa office. "This party has been sucking our blood since 2003, and look at them now: They are the richest people."

The protests began last Sunday in Basra, the oil-rich province that is also home to some of the worst poverty in the country. During the week, two people were shot dead by security forces attempting to contain the unrest as protesters targeted oil facilities and sought to shut down the port of Umm Qasr.

Friday's upheaval appeared to have been fueled at least in part by comments from Ayatollah Ali Sistani, the spiritual leader for the vast majority of Iraqi Shiites, indicating that he sympathized with the protesters grievances.

"It is not fair and it is never acceptable that this generous province is one of the most miserable areas in Iraq," said a statement issued on his behalf, referring to Basra.

According to preliminary election results, the party loyal to the populist cleric Muqtada al-Sadr won the most seats in the May election, and he has been in discussion with the other major Shiite parties to form a coalition government. All of those parties appeared to have had their offices targeted in the protests, apart from Sadr's, which has taken a stance against Iranian influence in Iraq.

Sadr indicated in a tweet on Friday that he also shared the protesters' concerns, calling their demonstrations "a revolution of the starving."

Although some politicians have alleged that he is fomenting the unrest, protesters reached by telephone deny that their actions are being driven by any political party.

"This is a revolution of the people," said Taie, the protester in Najaf. "We will not allow any political parties to get involved because we are protesting against them."