Police are investigating a bomb attack in the early hours of this morning on Microsoft's office in South Africa.

The "unidentified device" went off at 4.55am this morning in the courtyard next to the Microsoft canteen in the Johannesburg building. Only four security staff were on site at the time and no-one was injured, ITWeb reported.

Details of the attack are still sketchy. Police Inspector Willem de Villiers said: "Forensic analysts and the bomb disposal unit are combing the scene for evidence. At this time we cannot speculate on the motive or the device used to cause the explosion."

Microsoft SA insisted it was business as usual this morning. But staff were being advised to work remotely while police concluded their investigations of the site.

"With modern technology, we were up and running without any problems this morning, those at home just dialled in, and every one else is out seeing customers," said Microsoft SA MD Mark Hill.

No-one has yet claimed responsibility for the device. "It was a hell of a cowardly thing to do. I'm just glad that nobody was hurt," added Hill.

Photos of the blast can be found at IT Web