The head of the U.S. National Security Agency will likely face tough questioning about the government's controversial surveillance program when he appears before a congressional panel Wednesday.
General Keith Alexander's appearance before the Senate Appropriations Committee comes amid revelations his agency has collected e-mails other data from Internet companies through a program called PRISM.
Three of the world's biggest technology companies, U.S.-based Google, Facebook and Microsoft, are asking the Obama administration to let them reveal details of federal court orders to turn over information about their users to U.S. spy agencies. The companies say they want everything transparent and out in the open.
Edward Snowden, a former NSA contractor, revealed the story about PRISM and NSA monitoring of telephone calls to The Washington Post and the British-based newspaper The Guardian.
Snowden says it is important to reveal what he says is the government's massive surveillance program on private citizens.
The U.S. government says information gathered by the NSA has foiled terrorist plots. The Justice Department is investigating possible criminal charges against Snowden, who fled to Hong Kong last month, but whose exact whereabouts are not known.
The American Civil Liberties Union has filed a lawsuit in federal court challenging whether the NSA spy program is constitutional. The ACLU argues that the spying violates the rights to free speech and privacy. An ACLU attorney says the constitution does not let the government carry out unsuspected surveillance of every person in the country.