Ecuadorian President Lenin Moreno said Julian Assange has "repeatedly violated" the conditions of his asylum at the country's embassy in London, where the WikiLeaks founder has lived for more than six years.
Assange sought refuge there in 2012 to avoid extradition to Sweden, where he faced sexual assault charges that have since expired.
"He cannot lie, let alone hack into accounts or intercept private telephone calls" under the terms of his asylum agreement, Moreno told Ecuadorian radio on Tuesday.
Assange has refused to leave the embassy to avoid extradition to the United States to face charges over his website publishing huge caches of hacked State Department and Pentagon files in 2010.
Moreno told the radio association "Assange has too often repeatedly violated the agreement we have with him and his legal team", without saying whether Ecuador would withdraw asylum.
It comes after the Ecuadorian government filed a formal complaint to the UN special rapporteur on the right to privacy, Joseph Cannataci, accusing WikiLeaks of spreading private information linked to Moreno.
Photos, videos and private conversations appeared on portals such as Twitter and Facebook.
Moreno was also forced to deny allegations of corruption which surfaced on the website inapapers.org, with the president claiming he knew who was responsible for the accusations.
Relations between Assange and his embassy hosts have been deteriorating for months.
In October, Assange sued Ecuador for violating his "fundamental rights" by limiting his access to the outside world after his internet and mobile phone access were blocked back in March.
Quito accused him of breaking "a written commitment" not to interfere in Ecuador's foreign policies.
Moreno reiterated Tuesday that the government continues "to seek a solution" to Assange's situation.
