Gunmen in police uniforms kidnapped five Britons in Baghdad on Tuesday and the deaths of 10 US soldiers were announced, making May the deadliest month for the US military in more than two years.
The gunmen seized the Britons from a Finance Ministry building in eastern Baghdad. Two ministry employees who witnessed the kidnapping said at least one computer expert and several bodyguards were taken in the daylight raid.
Britain's Foreign Office in London said five Britons were kidnapped, and diplomatic sources said no other nationalities were involved.
"Officials from the British embassy in Baghdad are in urgent contact with the Iraqi authorities to establish the facts and to try to secure a swift resolution," said a spokesman.
The Canadian-based security firm GardaWorld said four of its British security guards, and the client, were kidnapped.
British Prime Minister Tony Blair, on a trip to Libya, said of the incident: "We will do everything we possibly can to help."
At least 38 people were killed when a bomb on a parked minibus exploded in central Baghdad and a car bomb exploded in a busy market in a southwestern Shi'ite district.
The US military said 10 soldiers were killed in Iraq on Monday, taking the total for May to 114, the deadliest month for US troops since November 2004 when 137 soldiers were killed.
Two were killed when their helicopter came down under enemy fire in Diyala province, where 3,000 reinforcements have been sent to combat a rise in violence. Troops heading to the crash site were struck by roadside bombs that killed six.
Two other soldiers were killed by a roadside bomb while on patrol in southern Baghdad.
The 10 deaths occurred as Americans observed Memorial Day services for their war dead.
The US military has said it anticipated heavier casualties when it began pouring thousands of extra troops into Baghdad and other areas as part of a security crackdown aimed at averting all-out sectarian civil war.
US President George W Bush won a bruising battle against Democrats over war funding this month but is under growing pressure from some in his own Republican Party to show progress in an increasingly unpopular war or start bringing troops home.
A total of 3,465 US soldiers have been killed in Iraq since the March 2003 invasion to topple Saddam Hussein. Tens of thousands of Iraqis have also been killed.
The worst month for US forces was when the 137 were killed in November 2004. The second worst was April that year when 135 were killed.
"I think if the current elevated level of US casualties continues, it will signal the failure of the Bush administration's strategy," said Loren Thompson, defence analyst with the US-based Lexington Institute.
Initially, there were conflicting reports over the kidnapping at the Iraqi Finance Ministry computer centre in Palestine Street, particularly over nationalities. Police and witnesses said Germans and Americans were among those abducted.
But the diplomatic sources, who declined to be named, said only Britons were involved.
A ministry official who witnessed the kidnapping said it took place as several computer experts gave a lecture on organising electronic contracts..
The gunmen entered the room led by a man wearing a police major's uniform, the official said.
The gunmen shouted, "Where are the foreigners, where are the foreigners?" she said.
Police said gunmen in a large convoy of vehicles, typically used by police, had sealed off streets round the building.
It was the first reported kidnapping of foreigners since the Baghdad security plan began in mid-February and the first time Westerners had been taken from inside a government building.
Kidnappings in Baghdad are a daily occurrence, usually for ransom or political motives. Men in camouflage uniforms took dozens of Iraqis from the Higher Education Ministry in November.
More than 200 foreigners and thousands of Iraqis have been kidnapped since the 2003 U.S. invasion, although there had been a recent lull in the seizure of foreigners.
Most of the foreign hostages who have been taken in Iraq have been released but others have been killed.
(Additional reporting by Ross Colvin, Aseel Kami and Mariam Karouny in Baghdad, Sophie Walker in London, and Noah Barkin in Berlin, and Kristin Roberts in Washington)