John Kerry: Spying Went Too Far in Some Cases
But says surveillance has prevented terrorist attacks
US Secretary of State John Kerry has said that in some cases, US spying has gone too far.
Mr Kerry is the most senior Obama administration official to have commented directly on an issue that has upset America's European allies.
He said he will work with the president to prevent further inappropriate acts by the National Security Agency.
His comments come as Asian countries have protested at claims that Australia was involved in a US-led spy network.