UK's intelligence agency has spied on Amnesty international's communications, the tribunal responsible for handling complaints against the intelligence services revealed.
On Wednesday, Amnesty International was notified through email by the tribunal that its communication had been accessed and stored by the Government Communications Headquarters agency, GCHQ.
In the email, the Investigatory Powers Tribunal (IPT) was correcting a 22 June ruling that had mistakenly identified one of two NGOs which it found had been subjected to unlawful surveillance by the UK government.
It made clear that it was actually Amnesty International and not the Egyptian Initiative for Personal Rights (EIPR) that was spied on, in addition to the Legal Resources Centre in South Africa.
The organisations were among ten NGOs that launched a complaint against suspected unlawful surveillance of their work by UK's spy agencies.
"After 18 months of litigation and all the denials and subterfuge that entailed, we now have confirmation that we were in fact subjected to UK government mass surveillance, Salil Shetty, Amnesty International’s secretary-general, said.
"It's outrageous that what has been often presented as being the domain of despotic rulers has been occurring on British soil, by the British government."
Sharif Elsayed-Ali, Amnesty's deputy director for global thematic Issues, told Al Jazeera that the organisation had been suspecting it was being spied on for a long time.
IPT's email made no mention of when or why Amnesty International was spied on, but Elsayed-Ali said: "We are speculating it could have to do with our investigation of violations being committed by the US and UK government."
The latest information may cause concern among human rights defenders and victims of abuses who have been communicating with the organisation.
Elsayed-Ali said that they try to secure their communication as much as possible, but they face threats of surveillance not only by the UK government but also by the governments where their contacts live.
The organisation has called for independent inquiry into how and why a UK intelligence agency has been spying on human rights organisations.
It also urged for "for significant legal reform, including proper pre-judicial authorisation and meaningful oversight of the use of surveillance powers by the UK security services".