A militia leader in the Democratic Republic of the Congo has reportedly been arrested over the killings of nine UN peacekeepers last week.
Bangladesh says it will not be deterred from peacekeeping
Floribert Ndjabu was arrested in a health clinic in the capital, Kinshasa, an intelligence source told the BBC.
His Nationalist and Integrationist Front is one of the militias operating in lawless north-eastern Ituri, where the Bangladeshi troops were killed.
The UN has suspended aid work in Ituri, saying it is too dangerous.
A spokesman for the UN humanitarian agency Ocha said that more than 50,000 people would be affected.
Neither the Congolese government nor the UN have officially confirmed the arrest.
Three more senior Ituri militia leaders, including two recently appointed as generals in the DR Congo army, are also being questioned in connection with the deaths.
Armed policemen have been stationed outside the luxury Kinshasa hotel rooms of Generals Goda Sukpa and Germain Katanga, both from Mr Ndjabu's group.
The BBC's Arnaud Zajtman in Kinshasa says their mobile phones have been switched off, as has that of Thomas Lubanga, another Ituri warlord.
Day of mourning
There are some 12,000 UN peacekeepers in DR Congo, following a 2002 deal to end five years of civil war.
But bitter ethnic fighting continues in Ituri.
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.
Bangladesh, which is one of the largest contributors to UN peacekeeping operations across the world, has 1,300 troops in DR Congo.
It has said the attack will not deter it from sending peacekeepers to DR Congo, or elsewhere.
Hundreds of mourners led by President Iajuddin Ahmed, attended funeral prayers in the capital, Dhaka, as the country observes a day of mourning.
The bodies of the soldiers have been taken to their own villages to be buried with full military honours.
Last week's attack was the deadliest against the UN mission in DR Congo since it was set up in 1999.