President Barack Obama says he will try to keep US intelligence-gathering operations in check - amid mounting European anger over American snooping.

Spain is the latest to summon its US ambassador to denounce the mass eavesdropping.

The Wall Street Journal said yesterday the National Security Agency had tapped the phones of some 35 world leaders, including close ally Angela Merkel.

Speaking to ABC News, Obama refused to corroborate such reports, citing the need to keep intelligence operations classified, but he acknowledged that the way US agencies go about their business is being reassessed:

White House spokesman Jay Carney says the President wants the right balance between privacy and security -  watch his press conference yesterday below at 3mins: