Amnesty International says the Azerbaijan government has barred it from visiting the capital, Baku, where the group planned to protest human rights violations ahead of the European Games.
Amnesty said it was forced to cancel its plans after the government said its delegates would not be welcome until after the games, which run from June 12-28.
The group intended to hold a briefing called Azerbaijan: The Repression Games to highlight Azerbaijan's crackdown on journalists, opposition members, and activists.
"Far from advancing the goals of press freedom and human dignity enshrined in the Olympic Charter, the legacy of these games will be to further encourage repressive authorities around the world to view major international sporting events as a ticket to international prestige and respectability," said Amnesty's Deputy Director Denis KrivoshAeev.
The move came as British political activist Emma Hughes was detained on arrival in Azerbaijan and told she was on a "red list" of people who cannot enter the country.