BAGHDAD, Aug 6 (AFP) - Six weeks after assuming sovereignty from the US-led occupation authority, Iraqi officials are vowing to crush violent militias and tame the bitter insurgency sapping their shaky authority.
The US military has backed the drive by engaging in two straight days of clashes with Shiite Muslim militiamen in and around the central Iraqi holy city of Najaf, claiming to have killed more than 300 fighters.
However, the unrest has also fanned out across Shiite central and southern Iraq, with insurgents targeting British-led troops in Basra and Amara and the Italians in Nasiriyah.
It marks the worst fighting since a June truce quelled a spring uprising spearheaded by radical Shiite leader Moqtada Sadr.
"We believe 100 percent that there should be no militias belonging to anyone anywhere in Iraq," government spokesman Gurgis Sada told AFP.
Armed groups who refuse to disband are "terrorists, criminals and they are against the law. Therefore, we will take all (necessary) steps," he said.
"There will be no more illegal militias," he insisted.
When asked if the campaign against the Mehdi Army could be extended to the Sunni Muslim insurgent bastions of Fallujah, Ramadi and Samarra, Sada said: "This concerns everywhere... Anywhere. Anytime. Whoever."
Najaf Governor Adnan al-Zorfi issued a 24-hour ultimatum to the Mehdi Army to leave the holy city or face the ongoing offensive.
"There is no compromise or room for another truce," he told reporters.
North of Baghdad, US troops and Iraqi security forces also launched a series of raids, dubbed Operation Cajun Mousetrap II, in an "uncompromising effort to kill or capture" insurgents in Samarra.
The operation followed a pledge from Interior Minister Falah al-Nakib that the government would not negotiate with the militias.
"We are going to fight these militias. We have enough power and enough strength to stop and kick those people out from the country," he said.
Asked by a journalist if he wanted Sadr dead or alive, he replied: "I want to arrest all who want to disturb the security of this country" and branding the Mehdi Army a terrorist organisation.
One day before the fighting kicked off in Najaf, the United States announced that it and its 31 partners in the US-led military coalition in Iraq had adopted a get tough policy to battle kidnappings and executions by extremists.
"As members of the multinational force in Iraq... we're united in our resolve to make no concessions to terrorists, nor to succumb to terrorist threats," US State Department spokesman Richard Boucher said.
"We're committed to making sure that the perpetrators of terrorist acts against our citizens and soldiers are brought to justice," he added.
Nevertheless, British forces based in Basra have stressed their intention to adopt a "softly, softly approach" in a bid not to incite further violence in their patch of southern Iraq.
UN advisor Jamal Benomar also called for the standoff to be solved through dialogue.
"If the violence continues, it will impact the substance of the national conference," he said.
The meeting, to be held in mid-August, will attempt to bring together 1,000 people from around the country to discuss Iraq's political future and elect a government advisory body.