At least 100 women raped in Guinea crackdown -group

* At least 100 women raped during Guinea protest crackdown

* UN experts investigating human rights abuses

CONAKRY, Nov 26 (Reuters) - Guinean soldiers raped at least 100 women during a crackdown on protesters in September, a human rights group said on Thursday.

The findings were released as United Nations experts began to investigate the repression, in which about 160 people were killed. The crackdown has drawn widespread condemnation and brought sanctions against the ruling military junta.

"We have recorded 100 cases of rape against women committed Sept. 28 and the two days that followed," said Thierno Maadjou Sow, president of the Guinean Organisation of Human Rights, which is working with the U.N. investigators.

"Most were schoolchildren, students, businesswomen, teachers, even journalists."

The organisation had found evidence that 20 victims were taken from a medical clinic to secret locations where they were drugged and raped repeatedly.

Three U.N. experts arrived in the West African nation, the world's top supplier of aluminum ore bauxite, on Wednesday to investigate the crackdown in which security forces used guns, steel pipes and knives on unarmed demonstrators gathered in a Conakry stadium.

Witnesses have said some soldiers violated women using gunbarrels and bayonets.

The demonstrators were protesting against the junta, whose leader Captain Musa Dadis Camara stepped back from a promise to opt out of elections intended to restore civilian rule.

The former soldier came to power in a coup in December following the death of strongman President Lansana Conte, briefly enjoying popularity among Guineans hopeful for a less ruthless regime.

International efforts to stave off new violence in the country have been complicated by reports Camara has hired foreign mercenaries to train a force to secure his place in power.

Sow said the U.N. investigation could be hampered by fear among witnesses of retribution if they cooperate.

"Many of the raped women have already been interviewed but today some of them are so fearful that we wonder how they will react," Sow said.

Camara and his junta allies have faced condemnation from African neighbours, Washington and Brussels, and were hit by travel bans, freezes on foreign bank accounts and an arms embargo. ((Reporting by Saliou Samb; Writing by Richard Valdmanis; Editing by Angus MacSwan,; Dakar newsroom +221 33 864 5076)) (For more Reuters Africa coverage and to have your say on the top issues, visit: