Nuri al-Maliki, the Iraqi prime minister, has called for MPs to withdraw confidence from one of his three deputy prime ministers in the deepening political crisis that worsened just as US forces completed their withdrawal.
"The prime minister sent an official letter to parliament, asking it to withdraw its confidence in Saleh al-Mutlak after his recent statements," Ali Mussawi, media adviser to Maliki, told the AFP news agency on Sunday.
Mutlak, who had been accused of being a supporter of Saddam's outlawed Baath party in the run-up to March 2010 elections in which he was barred from standing, said on Tuesday in a media interview that Washington was leaving Iraq "with a dictator".
And in a separate interview with his own Babiliyah satellite television channel, Mutlak charged, "Maliki is worse than Saddam Hussein, because the latter was a builder, but Maliki has done absolutely nothing".
In another development on Sunday, Tareq al-Hashimi, one of Iraq's two vice presidents, was escorted off a plane at Baghdad airport and two of his bodyguards were arrested on "terrorism charges".
Sources told Al Jazeera that Iraqi president Jalal Talabani intervened with the security authorities at Baghdad International Airport to allow Hashimi, his vice president, to travel to Suleimaniya.
Sunday's events came a day after the Iraqiya bloc said it was boycotting parliament in protest over the premier's alleged centralisation of power, as the US military was finishing its pullout from Iraq.
Al Jazeera's Omar al-Saleh reported from Baghdad that a member of Maliki's government had said the airport arrests were directed at the vice president.
"The president and the speaker of parliament intervened to end the incident and wait for a committee of five judges to review the evidence related to terrorism activities," our correspondent said. "This will have implications on the fragile coalition government and will throw the country in a political crisis."
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Security forces led Hashimi off an Iraqi Airways flight bound for Arbil and Suleimaniya in the northern autonomous Kurdish region, before arresting two of his guards, officials and a witness said.
Hiwa Osman, a Kurdish journalist and a passenger on the plane, told AFP that the flight, scheduled to depart at 5:30pm (1430 GMT), had been ready to go when officials boarded.
"Somebody came on board and wanted to check their identification, and asked them to leave the plane, and they left," Osman said. "Afterwards, they told us all to get off the plane."
Earlier, a security official told AFP that 10 of Hashimi's guards were detained over the past two weeks in connection with terror attacks.
Hashemi's office and spokespeople for Iraqiya did not respond to AFP requests for comment. A judicial spokesman also did not respond to multiple requests for comment.
On Saturday, Iraqiya, which emerged as the largest bloc in March 2010 elections and has 82 lawmakers in the 325-seat parliament, issued a statement saying it was suspending its participation in parliament to protest what it said was Maliki's centralisation of decision-making.
Iraqiya, which garnered most of its support from Iraq's Sunni Arabs, was out-manoeuvred for the premiership by Maliki, who, after finishing second in the elections, struck a deal with another group to broaden his power base and lead the government.
The bloc, which controls nine ministerial posts, has not pulled out of Iraq's national unity government.
Iraqiya said the government's actions, which it claimed included stationing tanks and armoured vehicles outside the houses of its leaders in the heavily-fortified Green Zone, "drive people to want to rid themselves of the strong arm of central power as far as the constitution allows them to".