The company said on its website that it will reveal more precise details as to what the problem was later today.

"Until then, we'd like to apologize and thank you. Precisely in that order. We know how difficult and frustrating the past two days have been. And still, your good wishes kept flowing in. Thank you for the amazing patience, trust and support!" said Skype's Villu Arak on the site.

Skype, which is owned by online auction company eBay, offers a peer-to-peer video and voice calling service that is used by approximately 220 million people worldwide.

The site first encountered the software problem last Thursday, with users all over the world unable to log on to use the Skype service, as a result.