WikiLeaks says Coinbase has suspended it from using the cryptocurrency firm's payments service.
Coinbase offers a feature that lets online shops accept cryptocurrencies as payments. WikiLeaks, which publishes confidential documents, also sells items such as T-shirts and posters, allowing people to pay in bitcoin.
WikiLeaks posted a tweet over the weekend showing a message it had received from Coinbase. The cryptocurrency firm said WikiLeaks was "in violation" of its terms of service, but did not specify why.
Coinbase was not immediately available for comment when contacted by CNBC on Monday.
WikiLeaks tweeted that it would "call for a global blockade of Coinbase" because it is "an unfit member of the crypto community."
WikiLeaks founder Julian Assange has been a big supporter of bitcoin. He claimed in October that WikiLeaks made a 50,000 percent return by investing in bitcoin in 2010. WikiLeaks has had a rocky history with payment processors such as Mastercard and Visa.
In 2010, Mastercard blocked its products being used to pay WikiLeaks. Paypal also restricted the account used by WikiLeaks after it said the group has violated its policy. Accepting bitcoin was a way for WikiLeaks to circumvent these payments firms.