Security has been tightened at shopping centres in the Kenyan capital, Nairobi, following warnings of terror attacks sent out by mobile phone.
Kenya was already on high alert
The BBC's Wellington Nyongesa in Nairobi says that all cars entering the centres are being checked, while policemen are patrolling inside the shops.
The text messages started arriving on mobile phones on Friday, leading to a huge decline in numbers of visitors to three shopping centres in the capital, Nairobi.
There have been increased fears of an attack by al-Qaeda in East Africa, Kenya in particular, in recent weeks.
British Airways has stopped flying to Kenya, while the United States has urged Americans not to travel to Kenya unless their trip is essential.
The Yaya, Sarit and Village Market shopping centres were all mentioned as possible targets in the messages.
Plse keep away from the big malls such as yaya, sarit, village mkt. am made 2 understand it is reliable info. Pass 2 others & lets pray
Car parks at the Sarit Centre were reportedly deserted over the weekend, while security was stepped up.
"We have increased our security precautions. We have taken on extra security guards and we are now randomly inspecting vehicle booths," said a spokesman for the centre, Peter Moll.
He told the that the scares had cost some 6-8 Kenyan shillings ($84,000 - $112,000) over the weekend.
A police source told our correspondent that he believed that the warnings were a hoax, however security has been increased.
"A security alert; plse keep away from the big malls such as yaya, sarit, village mkt. am made 2 understand it is reliable info. Pass 2 others & lets pray," read the text.
There is now no answer from the number which sent the messages.
The warnings followed reports that terror suspect Fazul Abdullah Mohammed, wanted in connection with the 1998 bombings of the US embassies in Nairobi and Dar es Salaam, was returning to Kenya.
More than 200 people were killed in those attacks.
Last November, 15 people were killed in a suicide attack on an Israeli-owned hotel near the coastal resort of Mombasa.