WASHINGTON (AP) _ Leaders of the Senate Judiciary Committee are seeking answers from the Obama administration about the use of surveillance technology that sweeps up basic cellphone data.

The bipartisan request from Sens. Patrick Leahy and Chuck Grassley was announced Wednesday.

The senators say they want more information from the departments of Justice and Homeland Security about how law enforcement agencies are using technology such as Stingray devices, which trick cellphones into identifying some of their owners' account information. That allows police to obtain cellphone information without having to ask for help from service providers.

They say FBI officials told their staff the FBI recently changed its policy and now seeks a warrant before using the technology, but with certain broad exceptions.

The Justice Department says it's reviewing the letter.