About 100 women have been sexually assaulted and many more injured in the latest mass rape by suspected rebels in eastern Democratic Republic of Congo, international aid workers and local media reported Thursday.

The attacks took place between June 10 and 12 in villages about 25 miles north of the town of Fizi in South Kivu, medical charity Doctors Without Borders (MSF) told Reuters by telephone.

"We have medical teams in the area, we were about to start on a mass vaccination program when we started hearing stories of rape relating to these events," said Megan Hunter, the mission head in South Kivu, from the Dutch branch of MSF.

"We've certainly treated over 100 women who say they have been raped or are suffering trauma," she said, adding they were working with Congo's Ministry of Health officials to confirm the numbers of victims.

The attacks have been blamed on a group of about 200 rebels who had been integrated into the Congolese army before deserting this month, U.N.-backed Radio Okapi said.

On Monday, the U.N. Office for the Co-ordination of Humanitarian Affairs (OCHA) said that the troops were reported to have looted health centers and cattle in the same area where the rapes occurred.

The U.N. peacekeeping mission in the country, MONUSCO, was unable to confirm the rapes but said it was investigating the reports, a spokeswoman said.

Citing Radio Okapi, the BBC quoted lawmaker Jean-Marie Ngoma as saying that that more than 60 women had been raped in a single village.

Eastern Congo remains deeply unstable following the end of a war in 2003 which left more than 5 million people dead. A multitude of armed groups continue to operate in the area, with both rebels and Congolese armed forces accused of committing atrocities against civilians.

Earlier this year, a colonel in the Congolese army was jailed for 20 years for ordering his men to rape more than 60 women in the town of Fizi.