House Intelligence Committee leaders said they are examining whether the contractor who leaked details about classified US spy programs had foreign help, while a Senate leader said she may propose restricting such workers' access to sensitive data.

The House committee is working with US intelligence agencies to do "a thorough scrub" of any connections to China after Edward Snowden fled the US for Hong Kong, Michigan Republican Mike Rogers, the committee chairman, told reporters in Washington today.

The picture of Edward Snowden, bottom, former CIA employee who leaked top-secret documents about sweeping US surveillance programs, is displayed on the front page of South China Morning Post at a news stand in Hong Kong Thursday, June 13, 2013. Credit:AP

He spoke after a classified briefing with General Keith Alexander, head of the National Security Agency.

"We need to ask a lot more questions about his motives, his connections, where he ended up, why he is there, how he is sustaining himself while he is there and is the Chinese government fully cooperating," Mr Rogers said.