An individual alleged to have links to Julian Assange has been arrested while trying to leave Ecuador, officials in the country said.
The man, said to be Swedish software developer Ola Bini, was held at Quito airport as he prepared to board a flight bound for Japan on Thursday.
Ecuador's interior minister Maria Paula Romo said a person had been arrested for allegedly conspiring against the country's government.
The development emerged as Assange spent his first night in custody after being convicted of breaching bail following a dramatic arrest at the Ecuadorian embassy in London, where he had been holed up for seven years.
He is facing extradition to the US on charges of conspiring to break into a classified government computer which, on conviction, could attract a maximum jail sentence of five years, according to the US Department of Justice.
UK Labour leader Jeremy Corbyn has called on the British Government to oppose any attempt to extradite him.
Ms Romo told CNN’s Spanish service: “We have information on how WikiLeaks would have intervened in domestic politics.
“Today a collaborator close to Julian Assange was arrested for investigative purposes. He has been living in Ecuador and was preparing to travel to Japan.”
British software developer Martin Fowler said he was "very concerned to hear that my friend and colleague olabini has been arrested in Ecuador".
A tweet posted under the Twitter handle olabini on Thursday referred to a press conference given by Ms Paula Romo in which she claimed there were “Russian hackers in Ecuador”.
“Very worrisome news — this seems like a witch hunt to me,” said another tweet on the account.
WikiLeaks accused Ecuador of acting illegally in terminating Assange’s political asylum “in violation of international law” on Thursday.
‘Continually a problem’
The Ecuadorian government had historically been sympathetic to Assange’s cause, but a regime change two years ago heralded a less supportive approach.
The country's ambassador to the UK, Jaime Marchan, said that in the time Assange had remained in the embassy he had been disrespectful, "continually a problem" and interfered in elections, politics and the internal affairs of other countries.
Mr Marchan added: “He has said that we were spying on him, he has said we were lying, we were agents of the United States.”
However, WikiLeaks editor Kristinn Hrafnsson said Assange had been thrown “overboard” by Ecuador, adding: “I thought it was horrible to treat an individual like that. I thought it was disgraceful the Ecuadorians would go back on their word.”
The US accuses Assange of assisting Chelsea Manning, a former US intelligence analyst, in breaking a password that helped her infiltrate Pentagon computers.
Mr Hrafnsson said a Grand Jury investigation included charges which could lead to decades in prison or even the death penalty under the Espionage Act 1917.
He told the Press Association: “We believe this indictment presented in the extradition request is only a part of the story — that there will be more later, that will be added on, more charges.”
Ecuador’s president Lenin Moreno said the UK Government had given him a written assurance that Assange would not be extradited to a country where he could face torture or the death penalty.
Foreign Office minister Sir Alan Duncan told the Daily Telegraph: "We don't extradite anybody to a country where they might face the death penalty without that routine assurance. We restated our policy."
As an Australian citizen, Assange will have the country's consular assistance available to him but will not get "special treatment", the prime minister, Scott Morrison, said.
“He will get the same treatment as everyone else, he will get the same support as everyone else,” he told ABC News.
While Theresa May and a number of ministers welcomed the arrest, Labour leader Mr Corbyn called on the government to oppose extradition.
He tweeted: “The extradition of Julian Assange to the US for exposing evidence of atrocities in Iraq and Afghanistan should be opposed by the British government.”
Assange, with grey hair tied into a pony tail and sporting a long beard, appeared at Westminster Magistrates’ Court where a judge accused him of behaving like a “narcissist” and advised him to “get over to the US” and “get on with your life”.
He spent almost seven years in the Ecuadorian embassy, where he sought political asylum in 2012 when he failed in his legal battle against extradition to Sweden, where he was wanted over two separate allegations, one of rape and one of molestation.
In May 2017, Sweden’s top prosecutor dropped the long-running inquiry into a rape claim against Assange, which he has always denied.
But his arrest on Thursday prompted the lawyer for a Swedish woman who alleged she was raped by Assange during a visit to Stockholm in 2010 to say they wanted the case reopened.
She told The Times she was “surprised and saddened” that Mr Assange would be handed over to the US.
“For me this was never about anything else than his misconduct against me/women and his refusal to take responsibility for this.
“Too bad my case could never be investigated properly, but the arrest will not change this, the case has already been closed.”
Prosecutors in Sweden have since confirmed that while the investigation has not been resumed, they are looking into the case.