Thousands of members of Saddam Hussein's Baath Party have been banned from holding government jobs.
The US wants to stop the Baath party as an organised force
The move will wipe out the Baath Party, putting "a stake in its heart", a senior official from the office of the new US civilian administrator in Iraq told reporters.
The decree was issued a day after the new administrator, Paul Bremer, gave notice that the coalition powers occupying Iraq were determined to eradicate Saddam Hussein's former power base.
US forces in Iraq have also launched a new crackdown on lawlessness, which has ravaged the country since the overthrow of the former regime five weeks ago.
The official, from the US Office of Reconstruction and Humanitarian Assistance (ORHA), said former Baathists were fuelling the crime wave and anti-American unrest in Iraq.
In other developments:
- German Chancellor Gerhard Schroeder gives his support to a US draft resolution calling for an end to sanctions against Iraq
- Amnesty International investigates allegations by several Iraqi prisoners of war that they were tortured by US and British troops
- The remains of 45 bodies are recovered from a mass grave in Karbala, the Associated Press news agency reports
The United States has been accused of failing to get to grips with the breakdown of law and order since the end of the war.
But one of the senior US generals in Baghdad, Major-General Buford Blount, said the number of military police in Baghdad would double to about 4,000 by the end of the month.
Hundreds of looters have been arrested
US forces have stepped up operations against looters, arresting about 300 since Wednesday, some reportedly as young as 10-years-old.
Major-General Blount said that, in future, looters would be held for up to three weeks, instead of just hours or days.
US troops have also put up Arabic-language posters around the capital warning looters of the damage they are doing to reconstruction efforts.
"The choice is yours - you can contribute to the reconstruction of Iraq and help build a prosperous Iraq, or you can condemn future generations to live in poverty. Do what your conscience dictates," the poster says.
The general said that about 90% of security problems were being caused by common criminals, many of whom had been freed from prison by Saddam Hussein in a mass amnesty in 2002.
The ban on Baath Party members from working in the public sector will affect between 15,000 and 30,000 Saddam Hussein loyalists, the ORHA official said.
An organised vetting process is to begin on Saturday involving interviews and the examination of records, he said
Up to 2,000 senior Baath Party members are still holding top jobs in Iraqi ministries, the official said.
He acknowledged that a Baathist purge would mean inefficiencies in the public sector for a while.
But he said: "That is a price we are willing to pay to be
sure that we extirpate Baathism from Iraq's society."
The ministries are mostly staffed by Baathists because in Saddam Hussein's Iraq, party membership was necessary for a good job.