Members of the public have been warned not to try to approach a gang who brandished a gun at a jewellery shop worker on the Isle of Wight.
A gang of at least three men raided Benzie yachting jewellery shop in High Street, Cowes, on Friday afternoon.
A woman working inside was threatened, but not hurt. The men took 15 watches.
Officers are appealing to hotels, guest houses and campsites on the island to report any suspicious activity or guests but not to approach them.
Det Insp Nick Heelan said: "Extra officers and resources are committed to tracking and arresting the suspects as quickly as possible.
"I would advise anyone who sees the suspects not to approach them directly, and call police immediately."
CCTV footage of the raid has been released by police and they appealed for any information about the gang.
Anyone offered quality second hand jewellery is also asked to contact Hampshire Constabulary.
No shots were fired during the raid from which the men fled with 15 watches
Officers are visiting other shops on the island known to stock high value goods to check on security levels.
During the raid, the men used sledgehammers to break the shop front window to access jewellery from the street.
They threatened the worker with a gun, which police say may have been a replica, as she stood in the doorway. No shots were fired.
Two women in their 20s, who were German tourists on a day trip to the island, were among several eyewitnesses who saw the raid, and caught the robbery on camera.
The robbers are said to have then driven away along the one-way Cowes High Street in a stolen silver Land Rover Freelander.
Land Rover abandoned
The vehicle was later found abandoned near the entrance to Northwood House in the town.
It had been reported stolen from an address in Rew Street, Gurnard, on Thursday.
Police are appealing for witnesses to the raid to come forward
Witnesses have told police they saw "a number of men" leaving a Land Rover at Northwood House before driving off in a large, older-style saloon car, but its make is unknown.
It was initially reported to have been a Volkswagen, and is possibly grey, silver or light green in colour, with damage to its rear, nearside wheel arch, and a registration plate beginning with "W".
A major air and land search for the men took place into Friday evening and officers carried out checks with Solent ferry operators, but the men were not apprehended.