Britain's foreign secretary says countries act within 'strict legal framework' and need to work in secret to defeat terrorists

William Hague, Britain's foreign secretary, has defended the country's intelligence-sharing ties with the United States as governments in both countries face criticism about spying on citizens.

Hague, speaking at the Ronald Reagan Presidential Library in Simi Valley, California, called intelligence-sharing between Britain and the US "unique and indispensable" at a time of unrest around the globe.

"In both our countries intelligence work takes place within a strong legal framework," Hague said. "We operate under the rule of law and are accountable for it. In some countries secret intelligence is used to control their people – in ours it only exists to protect their freedoms.

"We should always remember that terrorists plan to harm us in secret, criminal networks plan to steal from us in secret, foreign intelligence agencies plot to spy on us in secret and new weapons systems are devised in secret. We cannot protect the people of our countries without devising some of the response to those threats in secret."

His speech comes as the US continues to pursue National Security Agency leaker Edward Snowden. The former NSA contractor gained access to documents that he gave to the Guardian and Washington Post newspapers to expose what he contends are privacy violations by an authoritarian government.

Earlier this month in London Hague was forced to deny allegations that the UK government had used information provided by the Americans to circumvent British laws. "We want the British people to have confidence in the work of our intelligence agencies and in their adherence to the law and democratic values," Hague told parliament.

Snowden, who is charged with violating American espionage laws, touched off a global guessing game over his whereabouts after fleeing Hong Kong over the weekend, frustrating US efforts to bring him to justice. Russian President Vladimir Putin on Tuesday rejected US pleas to turn him over, saying Snowden remained in the transit zone of Moscow's Sheremetyevo airport and had not passed through Russian immigration, meaning he technically was not in Russia.