Police chiefs are urging shoppers to be extra vigilant in the wake of the discovery of a suspected bomb under a Tesco trolley in Basingstoke.
The explosion is being treated as a hoax by police.
The Met Police have urged anyone who finds a suspicious object or item to call 999.
Police said the trolley contained a package of crisps and a box of chips.
A statement said: “Anyone who sees a suspicious item or suspicious device or has any information is asked to contact police.”
Tesco said it was “working closely with our suppliers to investigate the incident and any subsequent developments”.
A spokeswoman said: “[The incident] was a hoax and we are providing support to the police.”
Theresa May has vowed to investigate claims of a bomb threat at a supermarket after a video appeared on social media showing shoppers being evacuated from the store.
She said: “If you spot something suspicious, call 999 immediately.
If you see a suspicious device on the trolleys, call the police immediately.”
“We are very much concerned about the incident, and we will do everything in our power to ensure that this does not happen again,” she said.
Last night, the Tesco spokeswoman said the incident occurred after a suspicious package was spotted by staff and staff alerted the police.
“At this stage we can’t provide further information on the cause of the incident,” she added.
The Met Police said: [The trolley] was contained and it was a safe item to leave the shopping centre.
We will be liaising with the relevant authorities.
“A video posted to social media appeared to show shoppers being taken to a nearby store, which was evacuated.
It was not clear if any of the items were connected to the bomb threat.
An earlier tweet showed people being evacuated on a trolley at the Teschos Basing St shop.
Tesco said the package was “safe” and contained “no explosives”.
Teschos customers were told to remain in their stores and call police if they saw anything suspicious.
‘It was a fake’A man is seen filming the incident from a car outside the Tescots BasingStoke branch.
A woman said people were being evacuated after the explosion.
One man was seen filming from a vehicle outside the supermarket.
Several people in the area were seen on mobile phones filming the scene.
Police officers in black uniforms were seen outside Tescos store, with a large number of police officers on the ground.
On Twitter, the hashtag #bakinginbasingstokes appeared to be trending in the UK, with some users asking for help to report the incident.
Some people have claimed they were evacuated as a result of the bomb scare.
#bakingincredible A photo tweeted by one person, captioned #bakershooting #bakeinbases, showed police officers standing outside a Tescos Basing Street shop.
Another picture tweeted by another user, captioning #bakeshooting #taylorsbasing, showed a large police presence outside a branch of Tesco.
People who live nearby said they saw police officers at the scene and police vehicles outside the shop.
One person said he was evacuated because he saw police on the road.
There were no reports of injuries.
Police have also warned of an increase in crime across the UK.
Hundreds of people have been arrested across the country since the start of the year for offences including theft, riot, drug possession and public order offences.