The White House has said that an investigation is under way after a former CIA employee leaked information about a covert US global surveillance programme that harvests internet and phone records of American citizens and foreigners.
Edward Snowden, 29, told Britain's Guardian newspaper that the government was gathering millions of phone and internet records.
He revealed himself as the source of the leaked information, insisting that he went public to protect the liberties of people around the world.
The White House has refused to discuss the investigation into what is one of the most significant leaks in US political history. Nor has it commented on Snowden, an employee of Booz Allen Hamilton, which was contracting for the National Security Agency (NSA).
"I believe he should be prosecuted to the fullest extent of the law," Peter King, senior Republican on the House Homeland Security Committee, said on Monday.
"I consider him right now to be a defector," he said.
Dianne Feinstein, the Democrat head the Senate Intelligence Committee, accused Snowden of committing an "act of treason" and demanded his prosecution.
The surveillance programmes were revealed last week by the Guardian and the Washington Post newspapers.
"I do not want to live in a world where everything I do and say is recorded," Snowden told the Guardian.
"That is not something I am willing to support or live under."
I can't in good conscience allow the US government to destroy privacy, internet freedom and basic liberties.
He also said he had no intention of hiding "because I have done nothing wrong", but was aware that his actions had made him a target for US agencies.
The full interview was uploaded to the internet shortly after it was published by the newspaper.
Snowden fled last month to Hong Kong, a Chinese territory that enjoys relative autonomy from Beijing. His exact whereabouts were unknown on Monday.
Although Hong Kong has an extradition treaty with the US, the document has some exceptions, including for crimes deemed political.
Any negotiations about his possible handover will involve China, but some analysts believe China is unlikely to want to jeopardise its relationship with the US over someone it would consider of little political interest.
Snowden also told the Guardian that he may seek asylum in Iceland.
Snowden leaked a presentation on the Prism surveillance system, which allows the NSA and the FBI direct access to the servers of US internet firms such as Google, Apple, Microsoft, Facebook and AOL.
It scooped emails, video chats, instant messages and more to track foreign suspects. The NSA is also collecting the telephone records of millions of US citizens, but not actual conversations.
President Barack Obama, the director of national intelligence James Clapper and others have said the programmes have been authorised by Congress and is subject to strict supervision of a secret court.