Eleven soldiers accused of raping more than 60 women in eastern Congo went on trial at a military court on Thursday.

The men are alleged to have carried out the attacks on New Years Day in the town of Fizi, in the unstable province of South Kivu, where abuses are rife amid clashes between the army, local and foreign rebels and militia fighters.

The United Nations has called Congo, where violence simmers eight years after the last war officially ended and ahead of a presidential election this year, the rape capital of the world, with mass rapes frequent and armed men seldom held accountable.

The accused -- who include their commanding officer Lieutenant Colonel Mutware Kibibi -- were charged on Thursday with crimes against humanity, including rape and imprisonment, according to a Reuters witness.

The tribunal, which is being held in the nearby town of Baraka and is expected to last up to 10 days, is being seen as a major test of whether the authorities are serious about ending impunity and bringing about justice.

Fidele Sarassoro, the deputy head of the U.N. mission in Congo, has called for a transparent legal process to punish those guilty of the Fizi attack, and warned that similar attacks would continue unless justice prevailed.

According to one U.N. estimate, more than 160 women are raped in eastern Congo every week. Aid workers say the majority of rapes by gunmen are never reported, let alone result in the conviction of those responsible.

An attack on a village in North Kivu province in mid-2010, when over 300 women were raped over the course of a few days, led to increased pressure for action and criticism of U.N. peacekeepers for not doing enough to protect civilians.

Legal aid group Lawyers Without Borders has accused the government of not investing enough in the country's overstretched and corrupt courts,