Nine United Nations peacekeepers from Bangladesh have been killed in an ambush in the Democratic Republic of Congo, the UN says.
Ituri has long been plagued by fighting between rebel groups
The attack happened on Friday morning in the north-eastern Ituri region, where 4,800 peacekeepers are deployed.
A UN spokesman said the troops were ambushed by "unidentified armed elements" while they were on patrol.
The UN force in Ituri also includes peacekeeping troops from Pakistan, Morocco and Nepal.
The UN's spokesman in Kinshasa, Mamdou Bah, said the ambush happened at about 0920 local time (0720 GMT) near the town of Kafe, 30km (19 miles) north-west of the provincial capital, Bunia.
The men killed were among 21 Bangladeshis on patrol in a camp housing civilians who had fled fighting in the region, the spokesman told the Associated Press news agency.
"These blue helmets were out there protecting people and they got ambushed while doing it."
A spokesman for UN Secretary General Kofi Annan called the attack a "criminal act" and urged the government to bring those responsible to justice.
The Bangladeshi army issued a statement confirming the deaths, but did not release the soldiers' identities. Officials said one of those killed was a captain.
The army said the bodies would be brought back to Bangladesh with the help of the UN.
Ituri has been the scene of bitter ethnic fighting for a number of years.
Violence between rival militias resumed in the mineral-rich province in December, and aid workers say tens of thousands of people have been displaced by the fighting - many fleeing to neighbouring Uganda.
UN forces have come under attack in Ituri before, but this is the first time that soldiers have been killed there, says the BBC's correspondent in the region, Ishbel Matheson.
Bangladesh, which is one of the largest contributors to the UN peacekeeping operations across the world, has 1,300 troops in DR Congo.
This is the second biggest loss of life for the Bangladeshi army while on UN peacekeeping duties.
In October 2003, 15 Bangladeshi officers died in a plane crash in Liberia.
Bangladesh's President Iajuddin Ahmed, Prime Minister Khaleda Zia and army chief Lt Gen Hasan Mashhud Chowdhury expressed deep shock at the death of the soldiers in Ituri.
In separate statements, the president and the prime minister said the contribution and sacrifice of the soldiers in maintaining peace would be remembered across the world.