Officials have been scrambled in response to a number of migrant boats crossing the English Channel.
Border Force, the coastguard and the RNLI are responding to the incident off the coast of Kent.
Up to four different vessels are reported to have been spotted.
The lifeguard was called just after 7am today to the incident, which is still ongoing.
It is understood the operation will likely last most of the day.
A spokesman for HM Coastguard said: "We are currently coordinating a search and rescue response to an incident off Kent, working with Border Force, Kent Police and the RNLI.
"An RNLI all-weather lifeboat from Dover and Border Force Seeker have been sent. We are committed to safeguarding life around the seas and coastal areas of this country.
"HM Coastguard is only concerned with preservation of life, rescuing those in trouble and bringing them safely back to shore, where they will be handed over to the relevant partner emergency services or authorities."
The Border Force has been approached for comment.
The BBC earlier reported that two boats had been brought in to Dover, and a third was being approached.
