By Pete Jones
GOMA, Democratic Republic of Congo (Reuters) - U.N. helicopters and artillery attacked M23 rebel positions near the city of Goma in eastern Democratic Republic of Congo on Wednesday in support of an offensive by the Congolese armed forces.
A 3,000-strong U.N. intervention brigade, with a tough new mandate to protect civilians and neutralize armed groups in the mineral-rich central African nation, sprang into action last week after it accused the M23 rebels of shelling Goma.
The M23 rebels, aware that their presence outside the city of 1 million people is key to their leverage in stalled peace talks, have fiercely resisted Congolese army efforts to push them back.
Army spokesman Lieutenant Colonel Olivier Hamuli said the U.N. brigade and regular U.N. peacekeepers had supported government forces with heavy artillery and attack helicopters.
"Combat is ongoing and there has been an intense bombardment of Kibati," said Hamuli, referring to a rebel base some 11 km (7 miles) north of Goma. "It's going well. We have not advanced much but M23 is gaining no territory."
Aftershocks of heavy artillery fire reverberated in some northern neighborhoods of Goma, causing panic, residents said.
The United Nations has taken a more proactive role since suspected rebel rockets landed in Goma on Thursday and Saturday. Five civilians were killed, according to Human Rights Watch.
Martin Kobler, the U.N. special representative to the Congo, told a news conference in Kinshasa that U.N. forces were supporting the Congolese army but could not guarantee the security of Goma.
Created in March, the U.N. brigade has a mandate for offensive missions, marking an aggressive step-up for U.N. peacekeeping operations in the region, which for years have been criticized for inaction.
Bolstered by the presence of the new brigade, Congolese President Joseph Kabila has effectively the ditched peace negotiations in the Uganda capital Kampala, analysts say, hoping the M23 can be pushed far enough not to present a threat to Goma.
The M23 humiliated the Congolese army and the United Nations' 17,000-strong peacekeeping force, known as MONUSCO, when it briefly occupied Goma in late 2012, forcing the opening of the talks.
Those negotiations have stalled, however, leading to renewed hostilities and escalating tensions between Congo and Rwanda.
U.N. investigators have accused neighboring Rwanda of supporting the 18-month M23 rebellion, an accusation Kigali has repeatedly denied.
The M23 rebels said in a statement the Congolese army and U.N. brigade had attacked its forces in Kanyaruchinya and Mutaho, to the north of Goma, with infantry, air strikes and heavy weapons.
(Additional reporting by Chrispin Mvano; Writing by Bate Felix; Editing by Daniel Flynn and Alison Williams)