Tens of thousands of Sunni Muslims blocked Iraq's main trade route to neighbouring Syria and Jordan in a fourth day of demonstrations against Shia Prime Minister Nouri al-Maliki.
The massive show of force on Wednesday marks an escalation in protests that erupted last week after troops detained the bodyguards of Sunni Finance Minister Rafia al-Issawi, threatening to plunge Iraq deeper into political turmoil.
"The people want to bring down the regime," chanted thousands of protesters in the Sunni stronghold of Anbar province.
It was the fourth major protest in less than a week in an area, which was once the heart of the deadly Sunni insurgency that erupted after the US -led invasion in 2003.
"This sit-in will remain open-ended until the demonstrators' demands are met, and until the injustice against ends," cleric Hamid al-Issawi told The Associated Press at the protest.
He accused Maliki of trying to create rifts among Sunni and Shia populations.
"These practices are aimed at drawing the country into a sectarian conflict again by creating crisis and targeting prominent national figures," the cleric said.
In an exclusive interview with Al Jazeera in Doha on Monday, exiled Vice President Tareq al-Hashimi leveled similar accusations against the Maliki government.
"On the ground, al-Maliki in fact, on a daily basis [is governing in a] sectarian way," Hashimi said.
"We don't have any option but to advocate and defend ourselves," he said in justifying the ongoing protests by Sunni-backed groups.
Hashimi is now living in exile in Turkey after being handed multiple death sentences for allegedly running death squads, a charge he dismisses as politically motivated.
The case is exacerbating tensions with Iraq's Sunnis, who see the detentions as politically motivated.
Earlier in the week, demonstrators gathered along a highway linking Baghdad with neighbouring Jordan and Syria.
They held banners demanding that Sunnis' rights be respected and calling for the release of Sunni prisoners in Iraqi jails.
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"We warn the government not to draw the country into sectarian conflict," read one. Another declared: "We are not a minority.''
Iraq's majority Shia rose to power following the 2003 US -led invasion that ousted Saddam Hussein's Sunni-dominated government, although the country's minority Sunni Arabs and Kurds do hold some posts within the government.
Maliki has defended the arrests of the finance minister's guards as legal and based on warrants issued by judicial authorities.
He also recently warned against a return to sectarian strife in criticising the responses of prominent Sunni officials to the detentions.
In a recent statement, the prime minister dismissed the rhetoric as political posturing ahead of provincial elections scheduled for April and warned his opponents not to forget the dark days of sectarian fighting "when we used to collect bodies and chopped heads from the streets".
The political tensions are rising at a sensitive time. Iraq's ailing President Jalal Talabani is incapacitated following a serious stroke last week and is being treated in a German hospital.
The 79-year-old president, an ethnic Kurd, is widely seen as a unifying figure with the clout to mediate among the country's ethnic and sectarian groups.
The discontent, however, extends beyond sectarian lines, according to Iraqi political analyst Sabah al-Mukhtar.
In an interview with Al Jazeera, al-Mukhtar said Iraqis "are very unhappy with the present regime" citing the breakdown of political dynamics between the Sunnis, Shia and Kurds, as well as lack of infrastructure and basic services.
"All these issues are making all of the Iraqis want change," al-Mukhtar said. "And don't forget, we have the Arab Spring. The Iraqis are saying, 'If everybody else revolted, why aren't we revolting against a regime, which is anyway imposed on us by an occupying force in 2003?'"