“They left without saying anything to us. They haven't used our services for awhile,” Mikael Viborg, CEO of Swedish web hosting company PRQ, told the Dagens Nyheter (DN) newspaper.
Viborg told the newspaper that he estimates stopped using his facilities about a month ago. He has since turned off the machines.
“They should have actually said they didn't want to use our services any longer. We sent a final bill a few weeks ago which still hasn't been paid,” he said.
Instead of servers based in Sweden, WikiLeaks now relies on machines based in France, according to DN, which used a traceroute to track the path traveled by internet traffic seeking to reach WikiLeaks.
But internet service provider Bahnhof denied the DN report that WikiLeaks had abandoned Sweden altogether.
According to Bahnhof board chair Jon Karlung, WikiLeaks has used servers at his company's facilities located on Södermalm in southern Stockholm since September.
“They are still in Sweden and are now customers with us. They have their homepage and database with us in a nuclear weapon-proof bunker under Vita Bergen,” Karlung told the TT news agency on Sunday, referring to the company's underground facilities housed in a former civil defence communications centre.
“We see that there is traffic going both to the homepage and the database right now, so it's absolutely in operation.”
Karlung explained that the Bahnhof servers now house the database which includes much of the material related to the Iraq war which WikiLeaks released in October.
“WikiLeaks has databases in many parts of the world, like in Paris and Amsterdam, for example, which is natural for what they do. But it's not true that they've left Sweden,” he said.
PRQ revealed in August, just two weeks before the surfacing of rape allegations against WikiLeaks founder Julian Assange, it had been helping the whistleblower websites 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," the 27-year-old Viborg told AFP at the time.
He said the company's server hall housed several hundred servers and was located "somewhere in Solna," some five kilometres (three miles) 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.
Sweden's constitutional protections for confidential sources was cited at the time as one of the reasons behind WikiLeaks' choice of Sweden as a home for its servers.
Rules on source protection are written into the Swedish constitution and effectively block individuals and government agencies from attempting to uncover journalists' sources. Revealing the identity if sources who wish to remain anonymous is a punishable offence.
However, the law only applied to websites or publications that possess a special publishing licence (utgivningsbevis) granting them constitutional protection, and WikiLeaks has not acquired the requisite paperwork, it was reported at the time.
WikiLeaks, which was founded in December 2006 and styles itself "the first intelligence agency of the people," published some 77,000 classified documents on the US-led war in Afghanistan in late July.
Then in October, the website released nearly 400,000 classified documents concerning the US war in Iraq.
An international warrant for Assange's arrest was issued by Swedish police on Friday. The WikieLeaks founder has been accused of raping one woman in Sweden and sexually molesting another while visiting Sweden in August.
He has strongly denied the charges and hinted that they could be part of a "smear campaign" against his whistleblower website for publishing classified US documents on the wars in Iraq and Afghanistan.