Mueller, testifying before the House Judiciary Committee, said all surveillance programs had been reported to members of Congress and vetted by the Justice Department, CNN reported. He said Congress can change the law to ban the tracking of Internet and telephone activity.
"If a change were to be made ... so be it, and we would follow the letter of the law," he said.
U.S. Rep. John Conyers, D-Mich., raised questions about the surveillance, revealed through leaks. The National Security Agency has been collecting data on electronic and phone contacts, although officials say a warrant is required to monitor the actual content of messages.
"It's my fear that we are on the verge of becoming a surveillance state, collecting billions of electronic records on law-abiding Americans every single day," Conyers said.
House Minority Leader Nancy Pelosi, D-Calif., called Thursday for the prosecution of Edward Snowden, The Hill reported. Snowden, now in Hong Kong, leaked information on the NSA surveillance while working for an agency contractor.
Members of the U.S. House Intelligence Committee said Thursday they don't believe Snowden had the kind of access he claimed.
Snowden this week claimed responsibility for the leak of information about the NSA's PRISM intelligence gathering program, which collected information on millions of cellphone calls.
Reps. Mike Rogers, chairman of the House Intelligence Committee, and Dutch Ruppersberger, D-Md., said Snowden "overinflated" his access and the actual technology of the programs.
"It's impossible for him to do what he was saying he could do," Rogers said after he and Ruppersberger met with NSA Director Gen. Keith Alexander.
The Hill reported authorities are trying to determine whether Snowden had any relationships with foreign governments.