US Director of National Intelligence James Clapper has told a House committee that determining "leadership intentions" is a basic element of intelligence gathering.

He was addressing the House intelligence committee amid a growing international row over reports the US has eavesdropped on citizens, diplomats and leaders of friendly nations.

He told committee chairman Mike Rogers, "It's invaluable to us to know where countries are coming from, what their policies are, how that would impact us across a whole range of issues."