The US/British coalition's failure to establish law and order in parts of Iraq has created a "vacuum" into which criminals and militias have poured, according to a British parliamentary committee.
The influential Foreign Affairs Select Committee also said that al-Qaeda has turned Iraq into a "battleground" with appalling consequences for the country's people.
The MPs concluded that an insufficient number of foreign troops deployed to Iraq has contributed to the deterioration in security.
The comments, in a new report, came just a day after a suicide car bomb north east of Baghdad killed 68 Iraqis and wounded 56 others in the deadliest terror strike since Iraq's interim government was installed.
In a report on the foreign policy aspects of the war against terrorism, the MPs said that the failure of countries other than the United States and United Kingdom to send significant numbers of armed personnel to Iraq has produced "serious and regrettable consequences".
The MPs said the British government should make a renewed effort to persuade other countries, including Islamic nations, to send troops.
Saudi Arabia has recently signalled that it might be prepared to take a lead in forming a Muslim security force for Iraq.
The committee further warned that Iraq's own army and police remain "a long way from being able to maintain security", and voiced concerns about the impact that violence might have on the elections planned for the start of next year.
In the report, the committee also expressed concern that key information on intelligence and alleged human rights violations by British personnel was withheld from senior Foreign Office officials and ministers.
The report highlights the now-notorious and discredited claim, in the British government's September 2002 dossier, that Saddam Hussein could deploy weapons of mass destruction within 45 minutes.
PA