By Patricia Zengerle
WASHINGTON (Reuters) - The secret U.S. court that reviews electronic surveillance and searches approves nearly every request it receives, but demands substantial changes to nearly one in four applications before giving the go-ahead, the court's top judge said in a letter released on Tuesday.
Amid ongoing controversy about U.S. spy agencies' collection of telephone and Internet data, Judge Reggie Walton of the Foreign Intelligence Surveillance Court told members of Congress that 24.4 percent of requests submitted from July to September had been overhauled.
He said he believed that percentage was typical, but said such monitoring would continue.
Annual statistics showing that the court approves more than 99 percent of applications had drawn criticism of the court, and charges that it worked too closely with government lawyers by rubber stamping their requests.
But that statistic reflects only the final decision, Walton, the presiding judge of the FISA court said in the October 11 letter to lawmakers.
"These statistics do not reflect the fact that many applications are altered prior to final submission or even withheld from final submission entirely, often after an indication that a judge would not approve them," he said in the letter, released by Senator Dianne Feinstein, chairwoman of the Senate Intelligence Committee, and other lawmakers.
Concern about surveillance - and privacy - has been growing since former National Security Agency contractor Edward Snowden in June began leaking information that the government collects far more internet and telephone data than previously known.
Some members of Congress have raised sharp questions about the extent of surveillance, while others, including Feinstein and other intelligence committee leaders in the House of Representatives and Senate, have defended data collection programs as essential to U.S. national security.
Several measures to change the laws covering U.S. surveillance programs are making their way through Congress.
Walton's letter was sent to leaders of the Senate and House Intelligence committee, as well as the Senate and House Judiciary committees.
(Reporting by Patricia Zengerle; editing by Jackie Frank)