WASHINGTON (AFP) - The US National Security Agency released its first "transparency report" Friday, as part of an effort to quell the firestorm over reports of its massive data collection efforts.

The NSA report said that in 2013, it obtained fewer than 2,000 orders from the secret Foreign Intelligence Surveillance Court.

That included 1,767 orders based on "probable cause" for an investigation, and 131 orders allowing the agency to collect incoming and outgoing phone numbers using a so-called "pen register" or "trap and trace." The agency said it obtained just one order using Section 702 of the FISA intelligence law, which facilitates gathering foreign intelligence data on non-American people, groups or organizations outside the United States.

But the number of "targets," which could be persons or organizations, was 89,138 last year.

The NSA said it made 178 applications under the law's bulk collection or "business records" provision - which allows the agency to sweep up vast amounts of telephone metadata.

That enabled the NSA to make a total of 423 specific queries last year to gather more data, along with queries on 248 "known or presumed US persons" and 172 other "individuals, entities or foreign powers." The report said 19,212 "national security letters" - administrative subpoenas that allow the FBI to collect information without a warrant - were issued last year, containing 38,832 requests for information.

The intelligence agency, which has come under fire following news of massive data collection capabilities, said it released the report under a June 2013 directive from President Barrack Obama.

The directive ordered the agency to "declassify and make public as much information as possible about certain sensitive US government surveillance programs while protecting sensitive classified intelligence and national security information." The agency said it would continue to do so on an annual basis.

- More information wanted -

The release came after the US House of Representatives passed a bill to curb the NSA's intelligence-gathering, although the measure remains in doubt, with some critics saying it was watered down.

Responding to the NSA release, Google law enforcement director Richard Salgado welcomed "a step in the right direction of increasing trust in both government and Internet services," but said further steps are needed.

Salgado said the government reports "in a manner that makes it impossible to compare its report with the report of companies" like Google, which can only provide a range of numbers about requests for data.

"We would like to see the federal government report on its national security demands with more information about the targets than it does today," he said in a blog post.

"Companies like Google can only provide a limited snapshot of how national security authorities are used. The Department of Justice, however, can provide a complete picture." The lack of information remains a sore point for civil rights and other activists.

Earlier on Friday, Greenpeace and the Electronic Frontier Foundation flew an airship over the NSA's data center in Utah to protest mass surveillance programs.

The airship carried the message: "NSA Illegal Spying Below" along with a link steering people to a new web site, StandAgainstSpying.org.