MEP Ana Miranda and Bundestag deputies Sevim Dagdelen and Heike Henzel had meetings scheduled with Assange in the Ecuadorian embassy, however, his sudden arrest upset these plans.
Instead, they arrived at the appointed time at Belmarsh High Security Prison, where Assange is reportedly being held in pre-trial detention, thought Scotland Yard has not confirmed Assange's whereabouts.
The parliamentarians said they sought to express solidarity with Assange, WikiLeaks, and all persecuted journalists.
"We strongly condemn the behaviour of the Ecuadorian government last week, flagrantly violating international norms: depriving Mr. Assange of asylum, Ecuadorian citizenship, his expulsion and subsequent arrest after summoning British police authorities to the embassy on behalf of the US authorities," reads the parliamentarians' statement.
READ MORE: Assange's Arrest: It's Confirmation That We Live in a Tyranny — Analyst
According to the deputies, recent developments in the Assange case set a dangerous precedent which threatens journalism, freedom of speech and press throughout the world.
"Our main task now as members of the Bundestag and the European Parliament is to prevent the extradition of Julian Assange to the US… The European Union must take measures to protect the politically persecuted publisher and journalist," they said in a statement.
"We are faced with a humanitarian imperative now that Assange is in custody in the UK, and an extradition warrant has been issued against him to the US, and after senior US officials, including President Donald Trump, have threatened the publisher with death… Extradition to Sweden should also be avoided, since it may also entail extradition to the US," the parliamentarians note.
According to them, “by hounding Assange,” the US Justice Department threatens “regular journalistic work and the very volatile sphere of protecting journalistic sources.”
In their statement, the deputies touched upon the rape charges against Assange. Swedish prosecutors received a request to reopen the case against WikiLeaks founder Julian Assange on rape charges and are currently studying it.
"We would note that Mr. Assange always expressed his willingness to cooperate with the Swedish authorities. The British authorities deliberately prevented such cooperation and later destroyed the materials pertinent to the case. We oppose the precipitate condemnation of Assange, aimed at his personal discredit. There is a presumption of innocence, everything else contradicts constitutional standards," the statement emphasises.
"We urge the British government not to extradite Julian Assange to the US… We urge the governments of Germany and Spain to grant political asylum to Julian Assange, and work together with the EU and the European Council to provide him with protection and prevent extradition," the report says.
As they spoke outside the prison, the deputies said they had prepared a statement in defence of Assange on behalf of a group of European politicians, and also intend to send a letter to British Prime Minister Teresa May on the same topic on Tuesday.