The US President Barack Obama has announced a ban on US eavesdropping on the leaders of close friends and allies.

In a major speech he has announced a series of reforms to the National Security Agency (NSA), triggered by revelations by whistleblower Edward Snowden.

The President is ordering changes to the vast collection of phone records by the US government.

The leaks by Snowden, a former security contractor, have shown that surveillance activities by the National Security Agency are far more extensive than previously thought.

They have outraged human rights groups, who say the right to privacy of citizens has been violated, and soured relations with US allies whose leaders have been allegedly spied on, such as Germany.

US officials insist spying operations are an essential tool in the fight against terrorists, but the president has ordered a review of the programmes in the wake of the leaks.

Edwards Snowden has sought asylum in Russia

In the latest revelations to stem from Snowden's leaked documents, The Guardian reported today that the NSA has been gathering nearly 200 million text messages a day from around the world.

That includes data on people's travel plans, contacts and credit card transactions.

Code-named Dishfire the NSA programme collects "pretty much everything it can", The Guardian said.

The newspaper said the documents also showed that the British spy agency GCHQ had used the NSA database to search the metadata of "untargeted and unwarranted" communications of people in the UK.

Today's Guardian made the claims

Snowden had already leaked secrets about mass collection of telephone data and other covert eavesdropping programmes before fleeing to Hong Kong and then to Moscow.

Russia has granted him temporary asylum. The US wants him back on charges that include espionage.