Edward Snowden reporters Glenn Greenwald, Laura Poitras back in US

Two reporters central to revealing the massive US government surveillance effort returned to the United States for the first time since the story broke and used the occasion to praise their exiled source: Edward Snowden.

Glenn Greenwald and Laura Poitras became a story of their own amid speculation they could be arrested upon arriving at New York's Kennedy airport. They were instead confronted by only reporters and photographers before fighting through traffic en route to a Manhattan hotel to receive a George Polk Award for national security reporting.

In remarks before an audience of other journalists and editors, the pair credited the courage of Snowden, the former NSA contractor who leaked the information for their story.

"This award is really for Edward Snowden," Poitras said.

Greenwald and Poitras had flown to Hong Kong to meet Snowden after the former defence contractor fled to the city with his leaked materials.

Greenwald said: "I hope that as journalists we realise not only the importance of defending our own rights, but also those of our sources like Edward Snowden."