Julian Assange speaking on the balcony of the Ecuadorian embassy in London
The Wikileaks founder has been living at the embassy since June 2012 to avoid extradition to Sweden to face questioning over the allegations, which he always denied.
Sweden dropped the case, but Assange remains subject to arrest in Britain for jumping bail.
It has now emerged that an operation initially called ‘Operation Guest’ and later ‘Operation Hotel’, along with other intelligence activity, ran up an average cost of at least $66,000 (£48,885) a month.
The operation had the approval of the then Ecuadorian president, Rafael Correa, and the then foreign minister, Ricardo Patino.
From June 2012 to the end of August 2013, Operation Hotel alone cost Ecuador $972,889 (£720,130), documents belonging to the country’s intelligence agency, known as Senain, reveal, The Guardian reported.
The Ecuadorians also rented a flat round the corner from the embassy to monitor activity there
Assange’s daily activities and changing moods, his interactions with embassy staff, his legal team and other visitors were monitored by security personnel and recorded in minute