British spies did not break laws when they used mass monitoring techniques revealed by former U.S. National Security Agency contractor Edward Snowden, the country's surveillance watchdog ruled on Friday. Civil rights groups and privacy campaigners, including Amnesty International and the American Civil Liberties Union, had argued the tactics used by Britain's three security agencies and disclosed by Snowden to the media last year did not comply with the UK's Human Rights Act.

"The 'Snowden revelations' in particular have led to the impression voiced in some quarters that the law in some way permits the Intelligence Services carte blanche to do what they will. We are satisfied that this is not the case," Britain's Investigatory Powers Tribunal (IPT) said in its ruling.

Snowden caused an international uproar when he disclosed details of the extent of surveillance and electronic monitoring by the NSA and its British equivalent, the General Communications Headquarters, or GCQA.

"We have ruled that the current regime, both in relation to Prism and Upstream (another NSA program) when conducted in accordance with the requirements which we have considered, is lawful and human rights-compliant," the IPT said.

The decision is expected to be appealed to the European Court of Human Rights.