WikiLeaks founder Julian Assange has had access to the internet suspended by the Ecuadorian government.
He has been living at the Ecuadorian embassy in London since June 2012, believing he will be extradited to the United States for questioning over the activities of WikiLeaks if he leaves.
Former Greek minister Yanis Varoufakis and musician Brian Eno said in a statement they had heard "with great concern" about the lost internet access as well as a ban on visitors.
"Only extraordinary pressure from the US and the Spanish governments can explain why Ecuador's authorities should have taken such appalling steps in isolating Julian," they said.
They added that the Ecuador government had only recently granted Mr Assange citizenship, saying it must have been "leaned on mercilessly" to stop attempting to provide a diplomatic route to safety and even drive the WikiLeaks founder out of the embassy.
"Clearly, Ecuador's government has been subjected to bullying over its decision to grant Julian asylum, support and ultimately, diplomatic status."
The Ecuador government said in a statement: "The government of Ecuador has suspended the systems that allow Julian Assange to communicate to the outside of the Ecuador embassy in London.
"The measure was adopted due to Assange not complying with a written promise which he made with the government in late 2017, by which he was obliged not to send messages which entailed interference in relation to other states."
WikiLeaks sources said there was no such agreement.