Police believe dissident republicans are responsible for placing firebombs in two NI shopping centres.
The area was later reopened
Two fire bombs were discovered in the Forestside complex, south Belfast. Army bomb experts made safe a device at Dunnes Stores on Monday at lunchtime.
On Saturday evening, another device ignited and damaged the Next clothes shop in the same complex.
Also on Monday, army experts made safe an incendiary device at Ards shopping centre in County Down.
Police are appealing to both shop workers and to shoppers across Northern Ireland to remain vigilant.
Nl Assistant Chief Constable Duncan McCausland condemned those responsible for planting the devices which, he said, had put lives and property at risk and caused unnecessary disruption.
"All right thinking people should be appalled by these attacks," he said.
"Some elements of society are intent on causing destruction and putting lives at risk,"
Mr McCausland said the devices were similar to those used by dissident republicans in the past.
DUP councillor in County Down, Jim Shannon, said the situation was very worrying.
"The people of Ards are angry. They are dismayed and disgusted," he said.
"Their answer is to get back to business and for the police and army to take very stern and strict action against those involved."
SDLP assembly member Carmel Hanna also condemned the firebomb attacks.
"I condemn utterly the spate of firebombs at Forestside shopping centre and elsewhere in the north which are a sign that, in the current atmosphere of political stalemate, we are drifting further into a state of low profile but immensely harmful violence," she said.
Police have warned shop owners across the province to be extra vigilant over the Easter period.