Nigerian soldiers have raped women and girls who fled the insurgency by militant Islamist group Boko Haram, Amnesty International has said.
Troops separated women from their husbands and raped them, sometimes in exchange for food, in refugee camps, the rights group added.
Thousands of people have also starved to death in the camps in north-eastern Nigeria since 2015, Amnesty said.
Nigeria's military has dismissed the allegations as malicious and false.
"These false reports, which are capable of derailing the good work being done by our patriotic and selfless soldiers, must stop," the military said in a statement.
Troops have been battling the insurgents since 2009 in Borno and other north-eastern states.
More than 30,000 people have been killed in the conflict, and about 1.8 million people have fled their homes.
The military has repeatedly been accused of carrying out atrocities, and the US, during the presidency of Barack Obama, refused to sell weapons to Nigeria, citing concerns about the military's human rights record.
However, the Trump administration has decided to press ahead with the sale of military aircraft and weapons, which Nigeria sees as vital to defeat the insurgents.
In its report, They betrayed us, Amnesty recorded the testimony of a 25-year-old woman who said a soldier raped her while she was pregnant.
"He knew I was five or six months pregnant. He said he saw me three times before. He didn't offer me any food, he called me and I ignored him but on the third day, he forced me to a room and raped me," she said.