GOMA, DR Congo (AFP) – Congolese troops returned to the strategic city of Goma on Monday, in line with a regionally brokered deal, as fresh information surfaced suggesting the rebel takeover of the town was backed by Rwanda and Uganda.

According to a report obtained by AFP, United Nations experts believe hundreds of Rwandan troops took part in the offensive by the M23 rebels who took Goma, while Uganda provided “logistics” support.

Rwanda and Uganda, which neighbour the Democratic Republic of Congo’s volatile, resource-rich east, have strongly denied involvement in the conflict.

The experts said their new investigation “strongly upholds” previous accusations that the neighbouring countries provided major backing to the rebels, who routed government forces before withdrawing from Goma at the weekend under a ceasefire accord.

The probe heaps more pressure on the Rwandan government over its role in the conflict as it prepares to take up a seat on the UN Security Council on January 1, diplomats said.

The rebels’ lightning capture of Goma on November 20 — eight months after the army mutineers launched an uprising against the government — had sparked fears of a wider war and major humanitarian crisis. Their withdrawal was widely welcomed.

Dozens of government army trucks crammed with heavily armed soldiers entered the regional capital in the afternoon, after trundling along the shores of Lake Kivu.

A battalion of around 600 men in total is expected to move into Goma, the main city in the mineral-rich Kivu region, while government officials have also begun to arrive back to reassert their authority after 12 days of rebel rule.

While the M23 fighters have left the city, rebels remained camped just beyond the outskirts, appearing to break a deal to pull back 20 kilometres (12 miles) from Goma, with residents fearing renewed clashes as the two sides edge closer.

However, the rebels claim they have not broken any agreement and that the fighters stationed around Goma are still in the process of pulling back.

“Our people are still there because you can only withdraw in stages, that is how it is done,” rebel commander Antoine Manzi said.

Ugandan army chief Aronda Nyakairima, speaking after a meeting in Goma with army chiefs of DR Congo and Rwanda, said he was “completely satisfied with the implementation of the accord so far” and that the rebels would fully pull back.

The rebels are demanding talks with the DR Congo government and have threatened to march back into Goma if Kinshasa reneges on a pledge they say was made to start negotiations.

DR Congo Interior Minister Richard Muyej Mangez said the government is ready to start talks “in the next few days”, but that the M23 should respect the agreement to withdraw the full 20 kilometres.

“The team for dialogue is already constituted,” Mangez told AFP in Goma.

Uganda will mediate the talks, which will begin once a full withdrawal has taken place, Nyakairima added.

Tensions remain high in the war-blighted region, with gunmen on Saturday attacking the giant Mugunga camp, which lies about 10 kilometres west of Goma and is home to up to 35,000 displaced people.

Residents were wary of the arrival of government soldiers, who, like the rebels, have been accused of civilian killings, rape and looting during the latest unrest.

Additionally, Rwanda said Sunday that Hutu extremist FDLR rebels based in DR Congo — Rwandans who fled their home country following the 1994 genocide there — had clashed on the border with Rwandan troops, but were pushed back.

The region, which borders Rwanda and Uganda, was the cradle of back-to-back wars that drew in much of the region from 1996 to 2003 and were fought largely over its vast wealth of copper, diamonds, gold and coltan, a key mobile phone component.

The instability there was exacerbated by the aftermath of the Rwandan genocide, when Hutus implicated in the killing of some 800,000 mostly Tutsi victims fled across the border after Tutsi leader Paul Kagame came to power.

Under the deal agreed by the rebels, the M23 will post 100 men at Goma airport alongside similar numbers of government troops, soldiers from neighbouring Tanzania and UN peacekeepers.

North Kivu regional authorities said the airport would re-open Thursday.

The M23 was founded by former fighters in a Tutsi rebel group whose members were integrated into the regular army under a 2009 peace deal that they claim was never fully implemented. Several of its leaders have been hit by UN sanctions over alleged atrocities.

Aid agencies are struggling to cope with the newly displaced, with some 285,000 people having fled their homes since the rebels began their uprising in April.