Hundreds of United Nations troops launched a major offensive in northeast Congo Friday to hunt down militiamen who killed nine Bangladeshi UN peacekeepers last month, a UN military source said.

"We are conducting a cordon-and-search operation as well as trying to apprehend the perpetrators of the killing of the Bangladeshis," the source said.

The operation northeast of Bunia, main city in the mineral-rich but lawless Ituri district, involved around 500 peacekeepers and started at around 07:30 local time (05:30 GMT), the source said.

Witnesses said UN helicopter gunships had been leaving Bunia airport throughout the morning.

The United Nations has been criticized in the past for being ineffective in reining in maurauding militias in the east of Democratic Republic of Congo, but has said it plans to step up operations to dismantle militia training camps in the region.

UN soldiers killed at least 50 militiamen in a fierce gunbattle involving helicopter gunships earlier this month at Loga village, five days after the Bangladeshi soldiers were killed in an ambush.

The clash was one of the biggest involving UN troops deployed in Congo, while the attack on the Bangladeshis was the worst single loss suffered by the UN peace mission since it began in the former Zaire in 1999.

An upsurge in fighting in the northeast since late last year has damaged efforts by the former Belgian colony to recover from a wider five-year war.

(China Daily March 12, 2005)