Julian Assange, the controversial founder of WikiLeaks, has been barred from using the Internet at the Ecuadoran Embassy in London, where he has been holed up for nearly six years, the Ecuadoran government announced.

In a statement on Wednesday, Ecuador said it suspended Assange’s ability to communicate with the outside world because he violated an agreement he signed with his hosts at the end of 2017 not to use his communiques to interfere in the affairs of other states. It was not immediately clear whether visitors would also be stopped.

“The Ecuador government warns that the conduct of Assange via his messages on social media puts at risk the good relations that Ecuador maintains with the United Kingdom, the European Union and other nations,” the statement said.

Ecuador did not cite any examples of this alleged breach.

Assange strongly supported separatist leaders in Spain’s Catalonia region who sought to secede last year. The head of that movement, Carles Puigdemont, the former regional president of Catalonia, was arrested over the weekend in Germany. Spanish authorities seek his extradition and return to Madrid, where he faces possible charges of treason and misuse of public funds.

Assange recently tweeted a stream of commentary about Facebook’s data breach, President Trump’s choice of John Bolton to serve as national security adviser, and allegations that Libyan dictator Moammar Gaddafi helped finance French politician Nicolas Sarkozy’s successful 2007 presidential election campaign.

Sources close to Assange revealed that the document he signed does not specifically address his tweeting and advocacy. Instead, Assange agreed to comply with Article 41 of the Vienna Convention on Diplomatic Relations of 1961, which states: 

“The premises of the mission must not be used in any manner incompatible with the functions of the mission as laid down in the present Convention or by other rules of general international law or by any special agreements in force between the sending and the receiving State.”

A WikiLeaks source, who declined to be named because communications with Assange have been cut off, said Assange signed the document when Ecuador was considering making him a diplomat, with all the protections that would imply. Such a move was not taken.

Instead, Wikileaks supporters say Assange sought refuge as a free-speech advocate who now finds his speech muzzled.

Assange, however, specifically sought refuge at the Ecuadoran Embassy, located in one of London’s most exclusive neighborhoods, in 2012 to avoid extradition to Sweden, where he was wanted for questioning about alleged sex crimes. Assange has denied the allegations. Swedish authorities have since shelved their investigation on grounds they could not get access to him.

Earlier this year, Assange lost two legal bids to quash a British arrest warrant issued after he skipped bail and fled to the embassy.

Assange has expressed fears that if he leaves the embassy, he will be arrested and extradited to the United States for questioning over WikiLeaks’s role in publishing a trove of classified U.S. documents.

Assange was granted Ecuadoran citizenship late last year, and the government said it has protected him. In its communique Wednesday, the South American nation seemed to be saying enough was enough.

Yanis Varoufakis, a former Greek minister, and Brian Eno, a British musician and record producer, said they had “great concern” when they heard Assange has lost access to the Internet and reportedly was no longer allowed to receive visitors.

“Only extraordinary pressure from the U.S. and the Spanish governments can explain why Ecuador’s authorities should have taken such appalling steps in isolating Julian,” they wrote in a statement.

This is not the first time his hosts have cut off his access to the Internet. In October 2016, the embassy temporarily denied Assange Internet access out of concern WikiLeaks was interfering in the U.S. presidential election. In the summer of 2016, the anti-secrecy site published hacked emails from the Democratic National Committee.

The Ecuadoran government said it cut off Assange’s Internet on Tuesday. 

In his latest tweets, posted Tuesday, Assange responded to an insult by  Foreign Office Minister Alan Duncan. In a debate in Parliament, Duncan called Assange a “miserable little worm” who should hand himself over to British authorities to face justice. 

Assange tweeted in response: “As a political prisoner detained without charge for 8 years, in violation of 2 UN rulings, I suppose I must be ‘miserable’; yet nothing wrong with being a ‘little’ person although I'm rather tall; and better a ‘worm’, a healthy creature that invigorates the soil, than a snake.”