Amnesty International, a campaign group which has accused the Kremlin of violating human rights with its bombing campaign in Syria, was evicted from its Moscow office on Wednesday.

The Moscow city government, from which Amnesty leased the premises in the Russian capital’s center, said the group was behind on the rent, but Amnesty said it had documents to prove it was up to date with payments.

Staff at the Moscow office told Reuters they arrived at work to find the locks had been changed, official seals had been placed over the doors, and the electricity had been cut off.

John Dalhuisen, Amnesty International’s Europe Director, said the eviction may be part of an official crackdown on civil society groups that criticize the Kremlin, but he said there were other possible explanations too.