A network outage at hosting provider Savvis has knocked a number of websites offline, including the web portal Lycos.

The outage occurred around 9am US Eastern Time yesterday morning, when a backup data line connecting Savvis's Boston data centres was accidentally severed, said Kathy O'Reilly, a Lycos spokeswoman. At the time, crews had been in the process of repairing the main line to the data centre, which was also down, she added.

With the two data lines out of service, the entire Lycos Network – including Lycos Mail and the Tripod web hosting service – was knocked off the internet, O'Reilly said. None of the data being stored by Lycos was affected by the incident, she added.

"It's basically a cascade of failures," she said. "Several other companies in the Boston area have also been affected."

The websites of PC Advisor sister publications CIO magazine and CSO magazine were also knocked offline by the outage.

Savvis could not immediately confirm how many customers had been affected by the failure, but in a statement from the company's technical service department, sent out just before 3pm US Eastern Time, the company said that two of its data centres, named B01 and B02, had been knocked offline.

"Savvis continues to work with the local telco vendor and hardware vendor to restore connectivity," the statement said. "An estimated time of resolution is unknown at this time."

Savvis, based in Missouri, is one of the largest hosting providers in the US.