The operations were being carried out in the Ituri region, where almost 250 Pakistani and South African troops on Tuesday killed at least 50 militiamen and destroyed two of their camps, he told journalists in Kinshasa.
Last week, 21 Bangladeshi soldiers of the UN peacekeeping force were ambushed by unidentified gunmen in the Ituri region, leaving nine dead and 11others wounded.
The killing of the militiamen was a "proportionate" UN reaction to that incident, said Collot d'Escury. "The militiamen have no choice but to disarm... If these armed groups continue to attack us, we will respond," he warned.
The killing of the Bangladeshis was the worst single loss suffered by the peacekeeping force in the country since its deployment in 1999. Ituri is one of the country's worst troubled spots where conflicts among local ethnic militias have left at least 50,000 dead and more than 500,000 homeless since 1998.