NEW YORK (Reuters) - A US judge ruled the National Security Agency's program that collects records of millions of Americans' phone calls is lawful, rejecting a challenge by the American Civil Liberties Union to the controversial counter-terrorism program.

Friday's decision by USDistrict Judge William Pauley in Manhattan diverges from a December 16 ruling by USDistrict Judge Richard Leon in Washington, D.C., who said the "almost Orwellian" program was likely unconstitutional.

The program's existence had first been disclosed by Edward Snowden, the former NSA contractor whose leaks have detailed the breadth of USelectronic surveillance and sparked a debate over how much leeway to give the government in protecting Americans from terrorism.

In a 54-page decision, Pauley said the program "vacuums up information about virtually every telephone call to, from, or within the United States."

But he said the program's constitutionality "is ultimately a question of reasonableness," and that there was no evidence that the government had used "bulk telephony metadata" for any reason other than to investigate and disrupt terrorist attacks.

"Technology allowed al Qaeda to operate decentralized and plot international terrorist attacks remotely," Pauley wrote. "The bulk telephony metadata collection program represents the government's counter-punch."

The judge denied the ACLU's motion for a preliminary injunction and granted a government motion to dismiss the case.

President Barack Obama has defended the surveillance program, but indicated a willingness to consider constraints.

The ACLU had no immediate comment. The White House was not immediately available for comment. A USDepartment of Justice spokesman said the department is pleased with the decision.

Rep. Peter King, chairman of the House Homeland Security Subcommittee on Counterintelligence & Terrorism, in a statement said Pauley's decision "preserves a vital weapon for the United States in our war against international terrorism."

The case is American Civil Liberties Union et al v. Clapper et al, USDistrict Court, Southern District of New York, No. 13-03994.