Prime Minister Nouri al-Maliki has appeared to lay the blame for rising sectarian violence in Iraq on the civil war in Syria, saying in televised remarks that such strife "came back to Iraq, because it began in another place in this region".
More than 215 people have been killed in five days of bloody violence that began with clashes between security forces and protesters in the north on Tuesday and have sent tensions soaring.
Speaking on Saturday, Maliki said: "Sectarianism is evil, and the wind of sectarianism does not need a licence to cross from a country to another, because if it begins in a place, it will move to another place.
"Strife is knocking on the doors of everyone, and no one will survive if it enters, because there is a wind behind it, and money, and plans."
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Maliki also called on anti-government protesters to expel "criminals" who targeted Iraqi forces in a statement made on Saturday, while the head of the Sahwa, an anti-al-Qaeda armed group, threatened dire consequences if fighters who killed four soldiers on Saturday were not handed over.
Gunmen killed the four army intelligence soldiers and wounded a fifth in Ramadi, west of Baghdad.
Al Jazeera's Omar Al Saleh, reporting from Baghdad, said: "Four soldiers in civilian clothes have been killed and a fifth injured near a protest site in Ramadi.
"The men were stopped by gunmen protecting the protest. It's not clear how things developed and what led to the killing. Some say they were intelligence agents, others say they were soldiers on leave and were stopped."
Anbar MP Ahmed al-Alwani announced late on Saturday that three men thought to be responsible had been handed over to the police.
The announcement came just hours after a commander of the Anbar police gave protesters 24 hours to turn in the men who killed the soldiers or face a heavy response.
Alwani said this was proof the tribes and protesters do not harbour criminals, our correspondent said.
Iraqi security forces have announced a curfew from 9pm until 4am in the large Sunni-majority Anbar Province in a bid to contain violence.
The ultimatum came after a statement by tribal leaders that they would turn the killers over to the judiciary, not the government or the army, if they were caught.
The US embassy in Baghdad praised the calls for justice in a statement condemning the violence.
"There is no justification for this crime, and we welcome the calls by local and national leaders in Anbar Province to bring the perpetrators to justice as soon as possible," the statement said.
"The United States stands firmly with the Iraqi people who seek to live in peace after so many decades of war."
Five other people, members of an anti-al-Qaeda group, were also killed on Saturday south of Tikrit.
In northern Iraq, Kurdish security forces have been deployed near the disputed city of Kirkuk, a Kurdish official said on Saturday.
The move is allegedly aimed at combatting fighters in the area after 40 people were killed in Kirkuk in the past week but, according to the AFP news agency, Staff General Ali Ghaidan Majeed, the commander of Iraqi ground forces, has called it a "dangerous development" and an attempt to reach the area's oilfields.
Thousands of protesters have gathered in cities across the country this week to voice their anger at the government, calling on the prime minister to step down and an end to discrimination against Sunnis.