Skype, the company whose eponymous computer program lets users make long distance phone calls over the internet, said Friday it had restored some users in Asia and parts of Europe, nearly 24 hours after a software bug caused a worldwide outage.

The outage began early Thursday afternoon. Users from Vietnam to Brazil to to the United States to Canada said they could not log on and make phone calls or send instant messages.

Skype said late Thursday that the issue was a problem with its software and not the result of a cyberattack. It said it still hopes for full service to resume by Friday.

The company, a division of online auction company eBay Inc., said that while some of its estimated 220 million users had reported successfully connecting, others still were unable to do so.

In a posting on the company's Heartbeat blog, Skype said that "even though it is too early to call out anything definite yet we are now seeing signs of improvement in our sign-on performance."

Skype has nearly 220 million accounts, with five million to six million users usually online at given time. In January, Skype reported that it had counted nine million users online at one time.

Skype urged users to allow the program to continue running and said they would automatically be logged on when the problem is resolved. It also temporarily disabled new downloads for the program.

Skype, founded by Niklas Zennstrom and Janus Friis, uses peer-to-peer technology to connect phone calls, instant messages and videos between its users. It runs on a variety of operating systems, including Windows, Mac OS X, PocketPC and Linux.

Besides computer-to-computer calls, Skype users also can use the program to connect to cellphones and traditional land line telephones.