NEW YORK -- Edward Snowden, who admitted leaking details of secret U.S. government surveillance programs, was fired by his employer Tuesday while the U.S. government considers criminal charges against him.

Booz Allen Hamilton said in a statement that it fired Snowden on Monday "for violations of the firm's code of ethics and firm policy." It said he had earned a salary of $122,000 a year. The firm called Snowden's actions "shocking" and said he had been a Booz Allen employee for less than three months.

President Barack Obama's administration is weighing whether to charge Snowden with leaking classified surveillance secrets while it defends the broad U.S. spy program that it says keeps America safe from terrorists.

Snowden, 29, has identified himself as the person who leaked top-secret information. He fled to Hong Kong in hopes of escaping criminal charges.

Booz Allen provides consulting services, technology support and analysis to U.S. government agencies and departments. Last year, 98 per cent of the company's $5.9 billion in revenue came from U.S. government contracts. Three-fourths of its 25,000 employees hold government security clearances. Half the employees have top secret clearances.

Snowden previously worked for the CIA and likely obtained his security clearance there. But like others who leave the government to join private contractors, he was able to keep his clearance after he left and began working for outside firms.

Once given security clearance, workers can access offices, files and, most important, dedicated communications and computer networks that are walled off from the public.

Snowden says he accessed and downloaded the last of the documents that detailed the surveillance program while working in an NSA office in Hawaii for Booz Allen.

The U.S. Justice Department, facing a global uproar over the programs that track phone and Internet messages around the world, is investigating whether the Snowden's actions were criminal.

Meanwhile, the European Parliament planned to debate the spy programs Tuesday and whether they have violated local privacy protections. EU officials in Brussels pledged to seek answers from U.S. diplomats at a trans-Atlantic ministerial meeting in Dublin later this week.

The global scrutiny comes after revelations from Snowden, who has chosen to reveal his identity. Snowden has fled to Hong Kong in hopes of escaping criminal charges as lawmakers including Senate intelligence chairwoman Sen. Dianne Feinstein accuse him of committing an "act of treason" that should be prosecuted.

Officials in Germany and the European Union issued calm but firm complaints Monday over two National Security Agency programs that target suspicious foreign messages -- potentially including phone numbers, email, images, video and other online communications transmitted through U.S. providers. British Foreign Secretary William Hague tried to assure Parliament that the spy programs do not encroach on U.K. privacy laws.

And in Washington, members of Congress said they would take a new look at potential ways to keep the U.S. safe from terror attacks without giving up privacy protections.

"There's very little trust in the government, and that's for good reason," said Rep. Adam Schiff, a Democrat who sits on the House of Representatives Intelligence Committee. "We're our own worst enemy."

Republican House Speaker John Boehner, however, said he believes Obama has fully explained why the program is needed. He told ABC's "Good Morning America" Tuesday that "the disclosure of this information puts Americans at risk. It shows our adversaries what our capabilities are and it's a giant violation of the law." He called Snowden a "traitor."

A senior U.S. intelligence official on Monday said there were no plans to scrap the programs that, despite the backlash, continue to receive widespread if cautious support within Congress. The official spoke on condition of anonymity to discuss the sensitive security issue.

The programs were revealed last week by The Guardian and The Washington Post newspapers. National Intelligence Director James Clapper has taken the unusual step of declassifying some of the previously top-secret details to help the administration mount a public defence of the surveillance as a necessary step to protect Americans.

Clapper came under fire from one of the staunchest critics of government surveillance programs, Sen. Ron Wyden, a Democrat. He said Clapper did not give him a straight answer last March when he asked whether the National Security Agency collects any data on millions of Americans.

Wyden, a member of the Senate intelligence committee, called for hearings to discuss the surveillance programs. He was also among a group of senators who introduced legislation Tuesday to force the government to declassify opinions of a secret court that authorizes the surveillance.

"The American people have the right to expect straight answers from the intelligence leadership to the questions asked by their representatives," Wyden said in a statement.

He was referring to an exchange with Clapper during a committee meeting in March when Clapper denied the NSA collected any type of data on millions of Americans, then softened his answer by adding "not wittingly." Wyden said he gave Clapper the chance to amend his answer but he did not.

One of the NSA programs gathers hundreds of millions of U.S. phone records to search for possible links to known terrorist targets abroad. The other allows the government to tap into nine U.S. Internet companies and gather all communications to detect suspicious behaviour that begins overseas.

The first explosive document Snowden revealed was a top secret court order issued by the Foreign Intelligence Surveillance Court that granted a three-month renewal for a massive collection of American phone records. That order was signed April 25.

Snowden also gave the Post and the Guardian a PowerPoint presentation on another secret program that collects online usage by the nine Internet providers. The U.S. government says it uses that information only to track foreigners' use overseas.

Believing his role would soon be exposed, Snowden fled last month to Hong Kong.

Although Hong Kong has an extradition treaty with the U.S., the document has some exceptions, including for crimes deemed political. Any negotiations about his possible handover will involve Beijing, but some analysts believe China is unlikely to want to jeopardize its relationship with Washington over someone it would consider of little political interest.