GENEVA — A report detailing hundreds of gruesome attacks against civilians in Congo over a 10-year period won't be released until October, the U.N.'s top human rights official said Thursday, after Rwanda angrily protested the findings in a draft version.

Drafts of the report — circulated to governments earlier this year and leaked to the media last week — accused Rwandan troops and rebel allies tied to the current Congolese president of slaughtering tens of thousands of Hutus in Congo in the 1990s.