* Congress revamps surveillance law after Snowden scandal
* Balancing privacy and national security concerns (New throughout with Alexander's comments on cell phone location data)
By Patricia Zengerle
WASHINGTON, Oct 2 (Reuters) - The U.S. National Security Agency has tested its ability to collect Americans' cellular telephone location data but does not have a program to collect that information, the NSA's director, General Keith Alexander, said on Wednesday.
Alexander told a Senate Judiciary committee hearing on the government's electronic eavesdropping that the NSA received data samples in 2010 and 2011 to test its ability to handle such information, but the data were never used for any other purposes.
"This may be something that is a future requirement for the country, but it is not right now," he said.
U.S. intelligence agencies' extensive collection of telephone and Internet data has been subject to scrutiny since former NSA contractor Edward Snowden began leaking information in June showing that surveillance was far more extensive than most Americans had realized.
Facing a public outcry, Republican and Democratic members of Congress are writing legislation to clamp down on the data collection and increase public access to information about it.
Democratic Senator Patrick Leahy, the Judiciary panel's chairman, said at the hearing he is working on a bill that would tighten oversight of the government surveillance programs.
Among other things, Leahy's program would end bulk data collection under Section 215 of the 2001 USA Patriot Act, which requires companies to turn over business records if a government request for them is approved by a secret intelligence court.
"I find the legal justification for this bulk collection to be strained at best, and the classified list of cases involving Section 215 to be unconvincing," Leahy said.
Intelligence agencies - and many members of Congress who strongly support their efforts - staunchly defend the data collection plans as essential for national security.
The Senate Intelligence committee is working on its own legislation addressing the eavesdropping issue, which would not go as far as Leahy's proposal. The intelligence panel is not seeking to stop the bulk data collection.
Leahy's legislation would also strengthen judicial review by the Foreign Intelligence Surveillance Court and require more oversight of the programs.
Democratic Senator Ron Wyden, a leading advocate for privacy rights, had asked Alexander about the cellular location data during a Senate Intelligence Committee last month.
Wyden has blasted the intelligence chiefs in the past for what he sees as dishonest answers during committee hearings. He said after Wednesday's testimony that he did not think Alexander had answered the question as completely as he could.
"After years of stonewalling on whether the government has ever tracked or planned to track the location of law-abiding Americans through their cell phones, once again, the intelligence leadership has decided to leave most of the real story secret - even when the truth would not compromise national security," he said in a statement.
At the hearing, Alexander also denied a New York Times report on Saturday that intelligence agencies tracked Americans' social media data to see whether they had terrorist connections.
The Senate Intelligence Committee was supposed to begin debating amendments to its legislation on Thursday, but that was delayed amid the government shutdown caused by Congress' budget impasse. (Reporting by Patricia Zengerle; Editing by Cynthia Osterman)