America's top intelligence official has called Edward Snowden's actions a "violation of sacred trust." By fleeing to Hong Kong, he has set up a major extradition battle. The debate has begun on whether he is a hero or a traitor.
Mr Snowden risks spending years in jail for speaking out and the National Security Agency has asked the US Justice Department to carry out a criminal investigation into the leaks.
President Barack Obama says the programs are authorized by Congress and subject to strict supervision of a secret court.
Director of National Intelligence James Clapper says they do not target US citizens. But Snowden claims the programs are open to abuse.
Mr Clapper said the revelations had done "huge, grave damage."
ITV News US Correspondent Robert Moore reports.