British media say Prime Minister Tony Blair will announce on Wednesday that a total of 3,000 British troops will leave Iraq by the end of the year.
Reports say Mr. Blair will announce in the House of Commons that 15,00 troops will withdraw in a few weeks and another 15,00 will leave later this year.
Some 7,000 British troops are now serving as part of the U.S.-led coalition in Iraq.
In violence Tuesday, Iraqi authorities say a suicide bomber killed at least seven people in an attack on mourners at a funeral in a mostly Shi'ite district in Baghdad.
Separately, a car bomb attack in southern Baghdad killed at least five people and wounded more than 10 others.
In the town of Taji, north of Baghdad, an explosion on a truck carrying fuel containers killed five people. Scores of people became sick after inhaling what officials suspect were toxic fumes. The cause of the explosion was not immediately clear.
Information for this report is provided by AP, AFP and Reuters.