A bipartisan group of 48 U.S. lawmakers wants two government agencies to explain a surveillance program in which Yahoo reportedly scanned all the messages of its email users on behalf of the FBI.

After recent news reports of the email scanning program, the Department of Justice and the Office of the Director of National Intelligence need to brief Congress about the efforts, the lawmakers said in a letter to the two agencies.

The first news reports about the program contained “conflicting reports about which legal authority was used” for the email scans, said the letter, organized by Representatives Justin Amash, a Michigan Republican, and Ted Lieu, a California Democrat.

“There is a significant confusion regarding the existence and nature of the program described by these reports and the legal questions implicated by the accuracy of specific details,” the letter added.

The DOJ and ODNI should provide a briefing to lawmakers “as soon as possible ... to resolve the issues raised by these reports,” the letter said.

In early October, news reports suggested Yahoo had scanned the messages of users of its web-based email service looking for code used by a foreign terrorist group. Yahoo called the initial news report, from Reuters, “misleading.”

Representatives of Yahoo and the DOJ didn’t immediately respond to requests for comments on the letter. Other lawmakers signing the letter included Representatives Zoe Lofgren, a California Democrat; Jason Chaffetz, a Utah Republican; Jared Polis, a Colorado Democrat; and Jim Sensenbrenner, a Wisconsin Republican.