WikiLeaks' lawyer, Baltasar Garzon, will be filing a case against the Ecuadorean government for violating the "fundamental rights and freedoms" of WikiLeaks' founder Julian Assange by cutting off his communications with the outside world, the organization wrote on Twitter. It is due to be heard in a domestic court next week.
WikiLeaks said that USA congressmen had written an open letter to Ecuador's president, Lenin Moreno, saying that in order to advance "crucial matters. from economic co-operation to counternarcotics assistance, to the possible return of a USAID mission to Ecuador, we must first resolve a significant challenge created by your predecessor, Rafael Correa - the status of Julian Assange".
Quito gave asylum to Assange in 2012, who took refuge in the legation to avoid being extradited to Sweden, where he was wanted for alleged sex charges now dropped.
Garzon told a press conference in Ecuador on Thursday that Assange was suing Ecuador Foreign Minister Jose Valencia over his "inhuman" living conditions at the embassy.
Ecuadorian President Lenin Moreno has said Assange's asylum deal can not be eternal.
The WikiLeaks founder, 47, was given a set of new house rules earlier this week, including cleaning his bathroom and taking better care of his cat.
Despite giving him political asylum, Ecuador's embassy has issued an increasing number of rules for Mr Assange to follow.
The statement slammed the so-called "Special Protocol", reportedly developed by Ecuador, as an unlawful means to censor Assange's "freedom of opinion, speech and association" by imposing conditions for his continued stay in the embassy.
In July, Ecuador's president Lenín Moreno said the whistleblower must leave the embassy eventually. The Australian fears, if he leaves the embassy, to be arrested and extradited and tried in the United States for the publication by WikiLeaks in 2010, many secret military and diplomatic documents, u.s.
That protocol requires journalists, lawyers and others meeting with Mr Assange to disclose details including social media usernames and the serial numbers of phones and tablets with Ecuador, which can than share the information "with other agencies".
WikiLeaks caused an worldwide storm in 2010 when it published a series of leaks from USA soldier Chelsea Manning.