The US National Security Agency sometimes uses data it collects for economic purposes, intelligence leaker Edward Snowden revealed in an extract of an interview with a German television station broadcast yesterday.
"If there is information, for example on Siemens, which is in the national interest, but has nothing to do with national security, they will still use this information," Snowden said.
The interview was carried out by a journalist for NDR, a regional chain belonging to public broadcaster ARD.
Under top secrecy, the chain last week in Moscow filmed the first interview with Snowden since he left Hong Kong last year to seek refuge in Russia.
On its website, NDR said Snowden said he was no longer had any confidential documents, as they had all been handed out to handpicked journalists. He said he no longer wanted to, or was able to, take part in any future revelations.
Other than the consequences of his revelations about NSA surveillance programmes, in the interview Snowden was also to address "his personal path" to leaking the information.
Snowden, 30, fled the US last May after revealing his government was collecting phone data from millions of citizens, monitoring vast amounts of private internet traffic and eavesdropping on the conversations of foreign friends and foes alike.
On Thursday, in a question-and-answer session on the Free Snowden website, Snowden ruled out returning to the US, where he said there was no chance of a free trial.
US Attorney General Eric Holder has said he was unlikely to consider clemency for Snowden.