Seven people hacked to death in a hospital were among at least 30 people killed in fighting at the weekend between the army, backed by U.N. troops, and Islamist Ugandan rebels in northeast Democratic Republic of Congo, local sources said on Monday.

Intelligence gaps, poor coordination and insufficient resources have rendered the Congolese army and the U.N. peacekeeping force ineffective against the armed ADF group that is estimated to have only a few hundred fighters.

Massacres on a similar scale have been a regular occurrence for more than a year. The ADF has operated in the area since the 1990s and funds itself by illicitly trading timber and gold.

Sunday's clashes broke out in the town of Eringeti, 55 km (35 miles) north of the town of Beni near the Ugandan border, when fighters from the ADF – a group led by Islamist radicals – attacked a military headquarters, according to the Center of Study for the Promotion of Peace, Democracy and Human Rights, a group that documents violence in North Kivu province.

At least four Congolese soldiers and 12 Islamist militants were killed in the clashes, while seven civilians were hacked to death with machetes at a hospital, according to a provisional toll, U.N. DRC mission spokesman, Felix Basse said.