It came as Sweden announced it was seeking Assange's arrest on suspicion of rape, setting up a possible future tug-of-war with the United States over any extradition of Assange from Britain.
It's not known what devices authorities removed from the embassy or what information they contained. But authorities said they were acting on a request by the U.S. prosecutors, leading Assange's defenders to claim that Ecuador has undermined the most basic principles of asylum while denying the secret-spiller's right to prepare his defense.
"It's disgraceful," WikiLeaks' editor in chief, Kristinn Hrafnsson, said in an interview with The Associated Press. "Ecuador granted him asylum because of the threat of extradition to the U.S. and now the same country, under new leadership, is actively collaborating with a criminal investigation against him."
Assange, 47, was arrested on April 11 after being handed over to British authorities by Ecuador. He is serving a 50-week sentence in a London prison for skipping bail while the U.S. seeks his extradition for conspiring to hack into military computers and spill secrets about U.S. operations in Iraq and Afghanistan.
Hrafnsson, who has visited the Australian activist in jail, said Assange saw his eviction coming for weeks as relations with President Lenin Moreno's government deteriorated, so he took great care to scrub computers and hard drives of any compromising material, including future planned leaks or internal communications with WikiLeaks collaborators.
Still, Hrafnsson said he fully expects Moreno or the Americans to claim revelations that don't exist. He called Monday's proceedings a "horse show" because no legal authority can guarantee Assange's devices haven't been tampered with, or the chain of custody unbroken, in the six weeks since his arrest.
"If anything surfaces, I can assure you it would've been planted," he said. "Julian isn't a novice when it comes to security and securing his information. We expected this to happen and protections have been in place for a very long time."
A group of Assange's supporters gathered outside Ecuador's Embassy in London to protest the judicial proceeding. Demonstrators put banners on the railings with images of Assange, his mouth covered by an American flag, and chanted "Thieves! Thieves! Thieves! Shame on you!"
Ecuadorian authorities said they will hand over any belongings not given to U.S. or Ecuadorian investigators to Assange's lawyers, who weren't invited to Monday's inventory-taking. Hrafnsson said he didn't have a full inventory of Assange's devices
Moreno decided to evict Assange from the embassy after accusing him of working with political opponents to hack into his phone and release damaging personal documents and photos, including several that showed him eating lobster in bed and the numbers of bank accounts allegedly used to hide proceeds from corruption.
Moreno's actions immediately were celebrated by the Trump administration, which was key in helping Ecuador secure a $4.2 billion credit line from the International Monetary Fund and has provided the tiny South American country with new trade and military deals in recent weeks.
"The Americans are the ones pulling the strings, and Moreno their puppet dancing to the tune of money," said Hrafnsson.
Separately on Monday, Swedish authorities issued a request for a detention order against Assange.
On May 13, Swedish prosecutors reopened a preliminary investigation against Assange, who visited Sweden in 2010, because two Swedish women said they were the victims of sex crimes committed by Assange.
While a case of alleged sexual misconduct against Assange in Sweden was dropped in 2017 when the statute of limitations expired, a rape allegation remains. Swedish authorities have had to shelve it because Assange was living at the embassy at the time and there was no prospect of bringing him to Sweden.
The statute of limitations in the rape case expires in August next year. Assange has denied wrongdoing, asserting that the allegations were politically motivated and that the sex was consensual.
According to the request for a detention order obtained by The Associated Press, Assange is wanted for "intentionally having carried out an intercourse" with an unnamed woman "by unduly exploiting that she was in a helpless state because of sleep."
AP writers Gonzalo Solano in Quito, Ecuador, and Jan M. Olsen in Copenhagen, Denmark, contributed to this report