Kenyan Tweeters have been cooperating with authorities to warn people away from the Westgate area west of downtown Nairobi, where gunfire, reports of hostages and rumours of deaths have swept digital media.

Saturday is a major shopping day at Westgate Mall, where coffee houses, clothing shops, a large supermarket and a food court are among the many attractions. The Kenya Red Cross says casualties are being taken to hospital, and many tweeters have called for blood donations.

At about 3:45 PM local time, Kenya's Interior Ministry tweeted that evacuation was underway and urged media "to be sensitive to the security operation and keep off". It said a few hostages had been rescued. The public has been asked not to try to phone friends or relatives who may be in the mall, where authorities have been trying to evacuate people. Kenya's Disaster Operations Center asked media to put in a time delay on live broadcasts. It thanked motorists giving way to emergency vehicles.

Among the Twitter feeds providing official information are: @InteriorKE, @PoliceKE, @NDOCKenya, and @KenyaRedCross.