Fears that dissident republicans are planning a pre-Christmas fire bombing blitz intensified tonight with the discovery of two incendiary devices in Belfast.
The fire bombs were discovered in the Big W store at Yorkgate in the north of the city and the Marks and Spencer store at Donegall Place in the city centre.
The Big W store had been cleared last night after reports that a device had been planted.
Nothing was found but after a telephoned warning today, a viable incendiary device was found.
Later, a similar device was found at Marks and Spencer. Both items have been taken away for forensic examination.
A police spokeswoman urged shopkeepers to search their premises for any suspicious items and to contact police immediately if anything is found.
She also called on shoppers to be vigilant and report anything suspicious to police.
It was the third incendiary device to be discovered in Belfast this week.
On Wednesday a crude device was found in a paint and wallpaper shop in North Street.
The security alert caused major disruption as the area remained sealed off for around four hours.