A Swedish Internet company said today it had been helping whistleblower website WikiLeaks since 2008 by hosting its servers at a secret basement location in a Stockholm suburb.

WikiLeaks "contacted us through a third party in Sweden a few years ago and ... their traffic goes through us," Mikael Viborg, the 27-year-old head of the PRQ Internet hosting company, told AFP.

He said the company's server hall housed several hundred servers and was located "somewhere in Solna," some five kilometres from Stockholm's centre.

WikiLeaks had purchased a so-called tunnel service, he said, meaning "the material itself is somewhere else but is sent through our machines so for someone downloading the material, it looks like it is coming from us."

He stressed however that "we have no control over what WikiLeaks publishes. We don't have any contact with them ... We have never talked with (WikiLeaks founder) Julian Assange and they never ask us before they publish something."

Viborg showed the entrance of PRQ's server hall to Swedish daily Dagens Nyheter, but refused to let the paper look inside and insisted the exact location not be revealed.

The company counts up to 600 customers, ranging from private individuals to international corporations, he told AFP, acknowledging that "some of the material sent out through our server hall is controversial and we want to avoid sabotage."

Viborg, who has a Swedish law degree and has served as a legal advisor to popular filesharing website The Pirate Bay, said PRQ had yet to be contacted by Swedish or US authorities about WikiLeaks' activities.

"I'm a bit worried about that happening, but I don't expect it," he said.

WikiLeaks, which was founded in December 2006 and styles itself "the first intelligence agency of the people," published some 70,000 classified documents on the US-led war in Afghanistan in late July.