The U.S. National Security Agency (NSA) is collecting location data daily from tens of millions of cellphones around the world, the Washington Post reported Wednesday. The records feed a database that stores information about the locations of at least hundreds of millions of devices, according to the officials and the documents, which were provided by former NSA contractor Edward Snowden.

In a statement, the American Civil Liberties Union expressed dismay at the sheer scale and scope of the program described yesterday.

"It is staggering that a location-tracking program on this scale could be implemented without any public debate, particularly given the substantial number of Americans having their movements recorded by the government," the civil liberties group said.

"The dragnet surveillance of hundreds of millions of cell phones flouts our international obligation to respect the privacy of foreigners and Americans alike," the ACLU said

The collected cellphone data are analyzed, the report said, adding tha the data analysis allows NSA analysts to identify cellphones and quickly retrace their movements to find hidden relationships among the people using them.

The analytics suite includes tools that can map the date, time and location of cellphones to find significant moments of overlap. "Other tools compute speed and trajectory for large numbers of mobile devices, overlaying the electronic data on transportation maps to compute the likely travel time and determine which devices might have intersected," the Post said in its report.

U.S. intelligence officials told the newspaper that the cell phone data collection program is legal and aims only to acquire information about foreign intelligence targets.