The centre of Milton Keynes remained paralysed yesterday for much of the morning while police mounted a search which located eight firebombs, writes Andrew Gliniecki.
People who were evacuated from their homes and spent the night in a community centre were allowed to return by 11am.
Two of the devices ignited early yesterday morning, causing damage at Habitat and BhS.
The devices are thought to be similar to those planted by the IRA in the Gateshead shopping centre in May.
No one has yet claimed responsibility.
Det Supt David Blair of Thames Valley Police said: 'This was quite horrific. One can only stress the callousness of people who plant them.'
The shopping centre was sealed off after devices were located by staff at Beatties toy shop and at the central library on Thursday at about 5pm. Two further firebombs were discovered at the library, and two at the John Lewis department store.
One of the devices ignited at BhS while police were in the building. A device placed inside a duvet at Habitat went off before the store had been searched.
The fire was quickly brought under control by the fire brigade, but damage was caused by the sprinkler system.
In May, 10 IRA firebombs were found at the Metrocentre in Gateshead, Europe's largest shopping centre.
In December last year, IRA incendiary devices were planted in London, Manchester, Blackpool, and in the Sainbury wing of the National Gallery in London.