Fleetwood's lifeboat has been launched following reports of a person in the water
Police were alerted at around 3.50pm today that a person had been seen entering the water close to The Mount in Fleetwood.
A search is currently underway involving police, coastguard and both Fleetwood lifeboats have been launched.
The coastguard helicopter has also been scrambled and is making repeated passes along the sea front as part of the search.
A coastguard spokesman said: "At the moment all we have is a report of a person in the water.
"Everything we have is being thrown at it."
Ambulance crews are on standby close to the scene.
The coastguard helicopter has been seen flying at low level up and down the sea front.
Later in the evening police issued an appeal for a woman called Joan, who raised the alarm, to come forward.
A spokesman said “We were alerted at around 3.55pm that a man had been seen in the water close to the Esplanade. The call was placed to the ambulance service from a telephone kiosk on the seafront by a woman called ‘Joan’, who did not leave her full details.
“We have been searching for the man ever since, along with the Coastguard, but he has yet to be located.
“We would now like to speak to the woman who placed the initial call so we can establish exactly what she saw.
“We would also like to speak to anybody else with information about who the man might be, or who might have seen him going into the water.”
Sgt Andy Lawless, of Fleetwood Police, said: “We still have a search underway following a call from a member of the public reporting a man having walked into the sea at Fleetwood.
“We are working hard to locate the man but need to trace the woman – possibly called Joan – who placed the initial call to find out a bit more information.
“Anyone else with information which could aid our search is also asked to contact us as soon as possible.”
Contact police on 101 quoting log number 915 of today (Monday).