WASHINGTON: The nation’s spy chief called on former intelligence contractor Edward Snowden to return a massive trove of classified documents on Wednesday during a congressional hearing on security threats that was dominated by heated exchanges over that security breach and the surveillance programs subsequently exposed.

Speaking before a Senate panel, James Clapper Jr. outlined an array of dangers to American interests, including a rise in cyberthreats and the emergence of Syria as a magnet for militants linked to Al-Qaeda.

But after skimming through those developments, Clapper focused his opening remarks on Snowden, delivering a blistering stream of criticism in which he described the former contractor for the National Security Agency as a hypocrite who has severely undermined US security.

Clapper said the documents exposed by Snowden have bolstered adversaries, caused allies to curtail cooperation with the United States, enabled terrorist groups to alter the ways they communicate, and put lives of US intelligence operatives at risk.

“Snowden claims that he has won and that his mission is accomplished,” Clapper said. “If that is so, I call on him and his accomplices to facilitate the return of the remaining stolen documents that have not yet been exposed to prevent even more damage to US security.”

Clapper did not clarify what he meant by “accomplices,” or whether he was referring to journalists who have received documents from Snowden. A spokesman said Clapper was “referring to anyone who is assisting Edward Snowden to further threaten our national security through the unauthorized disclosure of stolen documents related to lawful foreign intelligence collection programs. There were a number of sharply worded exchanges during the annual worldwide threat hearing — an ordinarily sober discussion — turning it into a platform for US intelligence officials and some of their critics in Congress to vent months of pent-up frustration with the Snowden fall-out.

At one point, Sen. Ron Wyden, D-Oregon, decried what he described as a “culture of misinformation” among US intelligence officials, cataloguing misstatements and falsehoods that had been exposed by Snowden.

Trust in those agencies “has been seriously undermined by senior officials’ reckless reliance on secret interpretations of the law and battered by years of misleading and deceptive statements,” Wyden said.

Among the most pointed examples was Clapper’s testimony before the same committee last year that US spy agencies did not gather data on millions of Americans. Months later, Snowden’s disclosures showed that the NSA had secretly compiled a database containing the phone records of nearly every American.

The recriminations over Snowden come as President Barack Obama has pledged to end the NSA’s collection of such records and underscored the extent to which Snowden-related damage control has been a major distraction for spy agencies struggling to keep up with rapidly shifting security threats.

US officials on Wednesday warned that political turmoil in the Middle East was accelerating the atomization of the Al-Qaeda terrorist network, with offshoots gaining strength in Syria, Yemen, Iraq and Egypt.

Clapper said that Syria has attracted about 7,000 fighters from as many as 50 nations beyond its borders, including a steady flow from the Middle East and Europe.