The United Nations has sent reinforcements to its Democratic Republic of Congo peacekeeping force near the eastern town of Beni after two soldiers were killed and 13 others wounded in an ambush on Tuesday.

“This morning we sent reinforcements to the Beni area—a rapid response unit to back up those caught in ambush,” Felix Prosper Basse, spokesman for the UN’s MONUSCO DRCongo mission, told AFP a day after two Tanzanian peacekeepers and two civilians were killed near Beni.

The attack was the second within 48 hours on UN personnel in the country. On Monday, a UN helicopter carrying MONUSCO’s military leader, Brazilian General Carlos Alberto dos Santos Cruz, was fired upon by unknown gunmen and forced to make an emergency landing.

Basse added that Santos Cruz would also travel to Beni—a trading hub in an area regularly targeted in attacks by Ugandan rebels from the Allied Democratic Forces (ADF).

Santos Cruz’s objective, Basse said, was to coordinate “robust measures” against members of the ADF suspected of staging Tuesday’s deadly ambush.

The shadowy ADF, which launched an insurgency in neighbouring Uganda against President Yoweri Museveni in the mid-1990s, is accused of killing more than 260 civilians in and around Beni between October and December last year.

In addition to the two Tanzanian peacekeepers killed in the ambush, 13 other UN troops of unknown nationality were shot and wounded, MONUSCO said.

On Wednesday, Ugandan police announced they had requested the extradition of ADF boss Jamil Mukulu, who was arrested last month in Tanzania. He is wanted on suspicion of a range of crimes, including terrorist acts and murder.

Last month, the ADF’s third most senior figure, Kasada Karume, was killed in fighting with Congolese troops, the national army said.

A further 28 ADF fighters have been killed, 22 wounded, and eight captured in battles in the region since the weekend, according to civil society sources.

“Today, despite what one might think… the ADF has never been so weak,” said General Jean Baillaud, deputy commander of the MONUSCO mission.

He added the process of “eradicating” the rebels had reached a “crucial phase.”

The slain Tanzanian soldiers were members of a 3,000-strong UN intervention brigade, itself part of a broader 20,000 MONUSCO force struggling to quell violence by scores of armed groups operating in the east of mineral-rich DR Congo.

The UN Security Council condemned the attack and reiterated that targeting peacekeepers may constitute war crimes under international law.

The members of the Council also expressed deep concern at the “security crisis” in eastern DR Congo, which they blamed on “ongoing destabilizing activities of foreign and domestic armed groups.

(AFP