The US Senate Judiciary Committee issued subpoenas on Wednesday to the White House and the office of Vice President Dick Cheney for documents about the warrantless eavesdropping program.
The committee also subpoenaed the Justice Department and the National Security Council over the program, which President George W. Bush authorized shortly after the Sept. 11, 2001, attacks.
"Our attempts to obtain information through testimony of administration witnesses have been met with a consistent pattern of evasion and misdirection," Democratic Senator Patrick Leahy, chairman of the committee, said in letters for the subpoenas.
He said there was no legitimate argument for withholding the requested materials from the committee.
The four parties subpoenaed were asked to comply before July 18.
The panel was seeking documents about internal disputes within the administration about the legality of the program.
In December 2005, The New York Times disclosed that soon after the Sept. 11 attacks, Bush authorized a highly classified program, without seeking approval from a special foreign-intelligence surveillance court, that allows the National Security Agency to monitor, without court warrants, international telephone calls and e-mails of US citizens with ties to al Qaeda suspects abroad.
The disclosure of the spying program caused a political uproar in Washington, and congressional hearings were held to investigate its legality.
After the program was challenged in court, the administration earlier this year put it under the supervision of the Foreign Intelligence Surveillance Court.
At the White House, spokesman Tony Fratto said they were aware of the committee's action and "will respond appropriately."
"It's unfortunate that congressional Democrats continue to choose the route of confrontation," he said.
(Xinhua News Agency June 28, 2007)
