No new United Nations peacekeeping troops will be sent to eastern Congo for at least a month after the Security Council failed to reach a decision on reinforcing its mission there.

Diplomats said there was broad agreement on the need to bolster the 17,000-strong force but scepticism from some quarters delayed a formal decision, which is now unlikely to come before the end of November.

Talks wrapped up amid reports of renewed chaos north of Goma, where hundreds of Congolese government soldiers rampaged through villages, raping women and children and looting homes as they pulled back ahead of an expected advance by rebel troops.

Laurent Nkunda, the renegade army general who leads the ethnic Tutsi rebels, has vowed to fight any troops, including UN peacekeepers, who aid the Congolese military. That will soon include troops from Angola, which responded to Kinshasa's call for help today when it announced it was mobilising forces to the region.

The chaos unfolding around the besieged town of Goma underlines the reluctance of some Security Council members to simply throw more troops at the problem. The UN is investigating reports of civilian massacres by rebel soldiers while the government's notoriously ill-disciplined troops stand accused of rape, looting and murder.

The peacekeepers' job is to keep the sides apart, but the rebels' advance on Goma has effectively placed them on the side of the government in defending the city from takeover. Thousands of troops from the 17,000-strong force, the largest in the world, have been redeployed to the east from other parts of the country. 95 per cent of the force, known as Monuc, are now in the east but the UN says it urgently needs another 3,000 soldiers and police.

Alain Le Roy, the head of UN Peacekeeping operations, said he believed the Security Council was sympathetic to the request. “There is no decision yet but the mood is evolving toward reinforcing the number of troops of Monuc,” he said in New York.

But Britain's Ambassador to the UN sounded a more cautious note. Britain has weighed the possibility of sending its own troops as part of a European Union force but only as a very last resort. "The Security Council faces many demands for peacekeeping," he said, referring to other missions in Somalia, Darfur and Chad.

"There isn't a bottomless pit of peacekeepers, so we do need to make absolutely sure we're making the best possible use of the troops that already exist in the largest peacekeeping force in the world."

Much of the violence in eastern Congo has taken place under the nose of the peacekeepers, raising serious questions about their efficacy. The UN is currently investigating how as many as 50 civilians were massacred last week by rebel troops in Kiwanja, north of Goma, where 140 peacekeepers are based.

Monuc's mandate allows it to open fire to protect civilians, something its troops failed to do in this instance. Peacekeepers did nothing to stop up to 800 Congolese soldiers rampaging through villages after fleeing Kanyabayonga, 60 miles north of Goma, ahead of a feared rebel advance.

Ban Ki-moon urged the Security Council to send 3,000 more troops and called on the warring sides to implement an immediate ceasefire to allow aid workers to reach more than 100,000 displaced people trapped behind rebel lines, adding that he was “very concerned by reports of targeted killings of civilians, looting and rape.”

Mr Ban will submit a report on the crisis to the council next week and no decision on extra troops is expected before it meets again on the issue on November 26.

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