The army in the Democratic Republic of Congo has suspended 12 senior officers in connection with an incident of mass rape in November, the UN has said.
The UN had issued an ultimatum saying that it would stop working with the two brigades involved in the allegations unless legal action was taken.
It says it has evidence of at least 126 rapes carried out in Minova by soldiers fleeing a rebel offensive.
Soldiers told the BBC that superior officers had ordered them to rape.
Armed groups in eastern DR Congo often use rape as a weapon of war.
The region's mineral riches have been plundered by numerous groups and countries over the past two decades.
On Thursday, the G8 group of nations announced what it called a historic pledge to work towards stamping out rape as a weapon of war, promising to provide $35m (£22.7m) to tackle the issue.
'Signal of commitment'
Minova, a market town to the south of Goma, was the briefly captured by M23 rebels at the end of last year.
The UN, which has 19,000 peacekeepers in DR Congo, identified a number of perpetrators from within the retreating Congolese army and demanded that they be prosecuted.
A spokesman for the UN peacekeepers said that following March's ultimatum investigations had now been launched, including interviews with victims and the interrogations of suspects.
"The commanding officers and deputy commanding officers of two units, as well as the commanding officers of eight other units, have been suspended and put at the disposal of the military prosecutor," the Reuters news agency quotes the spokesman, Kieran Dwyer, as saying.
"It is a signal of the commitment of the Congolese authorities, but we need them to follow through and hold accountable those who carried out these terrible crimes," Mr Dwyer told the AFP news agency.
In a BBC investigation broadcast on Thursday, soldiers, who all requested anonymity, admitted that they had raped women in Minova.
"We'd lost all hope. We weren't thinking like human beings," one of the soldiers told the BBC Newsnight team.
"It's true that we raped here... You see her, you take her away and have your way with her. Sometimes you kill her, when you finish raping her then you'll kill the child. You rape and carry on," another soldier said.
A staff sergeant said the order to rape came from above: "The commander gave us an order and he was the one who started to do it."
Some 800,000 people have fled the most recent unrest which started a year ago after the M23 fighters mutinied from the army.
They mainly come from the Tutsi minority group and say the government did not lived up to its promises in a 2009 deal, which saw rebel fighters incorporated into the army.
Last month, the UN Security Council approved plans to send a 2,500-strong brigade to eastern DR Congo to "neutralise and disarm" rebel groups.