Nairobi Westgate attack: 'Devastating situation' as stand-off continues

A security operation appears to be under way to clear militants from the Westgate shopping centre in the Kenyan capital Nairobi.

Kenyan authorities say that they carried out a controlled explosion to gain access to the building via the roof, says the BBC's Anne Soy at the scene in Nairobi.

It is not known what supplies might be available to any hostages still trapped inside the building, as the stand-off continues for a third day.