A United Nations armoured personnel carrier patrols through the city of Goma following the sound of shell fire and gunshots on November 19, 2012.

United Nations -

The United Nations put peacekeeper reinforcements on alert on Tuesday after hundreds of rebels moved around the key Democratic Republic of Congo city of Goma, UN officials said.

The United Nations raised new worries about the M23 and other rebel groups as it announced that at least 126 women were raped in a nearby town, mainly by Congolese government troops as they retreated from Goma in November.

The DR Congo government has been battling the M23, which UN experts say is backed by Rwanda, since March when the rebel group launched a mutiny.

The M23 briefly took Goma last month before withdrawing and agreeing to start talks with the government in Kampala.

UN peacekeeping chief Herve Ladsous briefed the UN Security Council about renewed tensions around Goma and preparations in case new hostilities erupt.

Afterwards, he told reporters hundreds of M23 fighters have been reported to be inside a ceasefire zone 20 kilometres around Goma.

“We are ready to send reinforcements to Goma very, very quickly if circumstances demand,” Ladsous said.

He said rebels are carrying out “erratic but worrying movements” around the city and the UN mission “is very much on the alert and patrolling constantly, including with aircraft.”

The UN has its biggest peacekeeping mission in DR Congo, with more than 17 000 troops who are spread thin in the huge country.

The M23 agitation could be linked to the talks between their leaders and the government in Kampala, Ladsous speculated.

Ladsous also warned that hundreds of fighters of another rebel group, the self-styled Democratic Forces for the Liberation of Rwanda (FDLR), had also been spotted around Goma.

The presence of the FDLR, created by perpetrators of the 1994 Rwandan genocide who fled to DR Congo, so near to the border is one reason for Rwanda's sensitivity to events in its neighbour, diplomats said.

The advance by M23 is just the latest episode of near continuous turmoil to hit the resource-rich region since the 1990s.

Hundreds of thousands of people are said to have died in that time while DR Congo has also become what the UN has called the “rape capital of the world.”

It said UN investigators had found that at least 126 women were raped around the town of Minova, near Goma, as government forces retreated between November 20 and November 30.

Ladsous said there had been “terrible violations” mostly carried out by government troops.

UN spokesman Martin Nesirky said earlier that nine government soldiers have been arrested so far - two for rapes and seven for looting - around Minova.

He added that UN officials raised concerns with DR Congo's vice prime minister and defence minister Mutombo Bakafwa Nsenda on Tuesday.

M23 rebels have also been accused of widespread abuses in regions they took over before a cease-fire was brokered by East African nations.

UN investigators have interviewed more than 200 people around Minova, said Nesirky. “According to preliminary findings, the UN mission has documented at least 126 cases of rape,” he said.

“The teams were also able to confirm the killing of two civilians including one minor,” he added. - Sapa-AFP