Customers were evacuated from a city supermarket after police received a bomb threat.
Morrisons on the Riverside retail park was closed for around an hour after a bomb threat was received by police, a Morrisons spokesman said.
Photographs showed police cars and dog units outside the doors.
Konstantinos Chalvatzis, a professor at the University of East Anglia, was shopping in the store at the time.
He said: 'There was a fire alarm while shopping and everyone went out. [It] felt all the way like a drill, there was police already out of the store when I entered and the alarm went off 15-20 minutes later.
'But judging by how elaborate this looks like now, it's hard to believe it's a drill.'
He said customers were now allowed back in the supermarket, but had not been given an explanation as to why the evacuation took place.
Although a Morrisons spokesman confirmed police had been made aware of a bomb threat.
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