WASHINGTON (AFP) - United States defence contractor Booz Allen said on Tuesday it has fired Edward Snowden, the 29-year-old employee who leaked secret US Internet and phone data surveillance programs to the press.

"Snowden, who had a salary at the rate of US$122,000 (S$153, 494), was terminated June 10, 2013 for violations of the firm's code of ethics and firm policy," the company said in a statement.

"News reports that this individual has claimed to have leaked classified information are shocking, and if accurate, this action represents a grave violation of the code of conduct and core values of our firm," it said.

Previous reports have said Snowden earned US$200,000 per year, and it was not clear from Booz Allen's statement whether this was false or whether Snowden received any bonuses or allowances in addition to his salary of US$122,000.

The company said it would work closely with authorities investigating the security breach at the National Security Agency, where Snowden had worked as a contractor - for the last three months as a Booz Allen employee.