GOMA, Democratic Republic of Congo — The tropical rain turns Goma’s lava-blackened streets to slurry as thick grey storm clouds thunder overhead.

For hours the city is on pause as its hawkers and traders, soldiers and civilians shelter from the relentless downpour. Then the rain stops and the streets burst to life again.

A year ago this chaotic lakeside city lived in fear. It was on the brink of being overrun by a rebel army made up of ethnic Tutsi fighters supported with arms, money and volunteers from neighboring Rwanda.

Goma is no longer under siege but the surrounding countryside of the eastern Congo remains embattled. It is a complicated war that includes rebel groups, warlords, ethnic enmities and United Nations forces. Currently the Congo army and the United Nations are fighting together against the rebels of the FDLR.

FDLR rebels in eastern Congo.

(Jan-Joseph Stok/GlobalPost)

The background to these military offensives is the Rwandan genocide of 1994. The territory being fought over contains valuable mines from which all sides are getting the money to fund the war. Those suffering the most are the people of eastern Congo.

The current war started early this year after the arrest of dissident Congolese general Laurent Nkunda. At the height of his power Nkunda — tall and slim, bespectacled and clutching a silver-topped cane — was the world’s most recognizable warlord.

But in January an unexpected detente between the presidents of Rwanda and Congo, Paul Kagame and Joseph Kabila, led to Nkunda’s arrest in Rwanda and subsequent house arrest in the Rwandan capital Kigali.

In return for taking Nkunda out of play, Kagame was given the opportunity send troops into eastern Congo and hunt down the FDLR, a rebel group made up of ethnic Hutu fighters who he blames for the 1994 genocide in Rwanda that killed 800,000 Tutsis and moderate Hutus in 100 days of low-tech slaughter.

The current fighting in eastern Congo can be traced back to Rwanda’s 1996 invasion of its larger neighbour in a bid to revenge itself on these "genocidaires." The International Rescue Committee (IRC), an American aid organization, blames the fighting since then for the

deaths of more than 5 million people in the region, mostly from disease and malnutrition.

A five-week joint Rwandan-Congolese operation began in January and was followed by another U.N.-backed Congolese operation that started in March. The aim of both "Umoja Wetu" and "Kimia II" was to disarm the Democratic Forces for the Liberation of Rwanda (known by its French acronym, FDLR).

But after months of jungle skirmishes and village battles that have displaced a fifth of the population, left hundreds of civilians dead and thousands of women raped, the FDLR is no closer to being defeated.

The reasons why are explained in a report compiled by a panel of U.N. investigators and that has been obtained by GlobalPost.

According to the report a series of businessmen in Burundi, Tanzania and Uganda are trading with the FDLR to transport valuable minerals out of their territory and bring deadly weapons in. The tin ore, gold, diamonds and coltan (used in mobile phones) illegally dug from the earth of eastern Congo are exported and end up in western consumer electronic goods.

The report also detailed how some Congolese army officers provide the rebels with arms even as their own troops are fighting to defeat them.

The 17,000-strong U.N. peacekeeping mission, MONUC, comes in for criticism for backing the Congolese army in the latest offensive against the rebels. The campaign started in March and is known as Kimia II. The U.N. report talks of “the possible contradiction” between the U.N.’s mandate to protect civilians and its support of the Congolese army which it says “continues to commit abuses against the civilian population, and conducts military operations in disregard of protection of civilians and for humanitarian law.”

New York-based Human Rights Watch has catalogued a litany of rapes, murders and forced displacements committed this year by Congo’s national army as well as various rebel groups.

The pressure is mounting against the FDLR. Last month its top leaders were arrested in Germany and charged with war crimes and crimes against humanity committed in eastern Congo.

Ignace Murwanashyaka and Straton Musoni await trial in a German court but their arrest alone is a blow to the FDLR as one recently defected fighter admitted to during a recent interview at a repatriation camp in Goma.

“We feel very, very bad because of the arrests. Ignace was our leader,” Innocent Rakundo told GlobalPost. The 35-year old FDLR corporal said he deserted the rebel group soon after the arrests, fed up with being hunted through the forests and shot at. He now hopes to return to Rwanda for the first time since fleeing Kagame’s forces in the aftermath of the genocide.

It is not just the rank-and-file who acknowledge the impact of the recent arrests. In a telephone conversation, Laforge Fils, the group’s spokesman in North Kivu, said: “The arrests are unjust and not justified.”

“It shows that the international community doesn’t want to respond to the wishes of the people of the Great Lakes region,” he said with a wounded tone in his voice. “The problem of insecurity in this region is to be found inside Rwanda but instead of solving the problem at its source they want to solve it superficially.”

He repeated calls for dialogue with Kagame, something the Rwandan leader has ruled out.

U.N. officials in charge of trying to persuade FDLR fighters such as Rakundo to lay down their weapons concede that for all their successes — over 100 rebels deserted last month — the group continues to recruit both volunteers and conscripts meaning its estimated strength is thought to have remained stable at perhaps 6,000 to 8,000.

Although its movement is constrained it still has strongholds dotted about the provinces that border Lake Kivu. One is just a few miles outside the city of Goma on the slopes of the Nyiragongo volcano whose lava flows cut through the city in 2002.

Intrepid tourists used to make the arduous trek up to the crater’s edge to stare transfixed into the lava lake below. Last year Nkunda’s armed men prowled this wild landscape, now it is the FDLR once again.

The groups may change but for the Congolese people the insecurity remains the same.

Editor's note: This story was updated to remove a reference to a U.S. company named in the U.N. report on conflict minerals. Click here for more details on this correction.