A search is under way after an empty dinghy was spotted drifting off the coast of Kent.
An empty rigid-hulled inflatable boat (RHIB) was seen a couple of miles from Walmer and a number of lifejackets have also been seen near Shakespeare beach in Dover, some 15 miles (24km) away.
Four lifeboats have been launched and the Coastguard helicopter scrambled.
The Home Office said: “Border Force is currently dealing with an ongoing small boat incident off the Kent coast.”
HM Coastguard said it is assisting Border Force officials.
The RNLI said an earlier report that a migrant had walked into Walmer lifeboat station was mistaken.
On 18 February, 34 people – including men, women and children – were brought to shore at Dover from a small boat discovered in the Channel.
At least 91 people have made the 21-mile journey between France and England in small boats this year.
Analysis – Simon Jones, BBC South East
The Home Office is keen to point out that it’s dealing with what the Home Secretary, Sajid Javid, declared to be a major incident at the end of last year.
It says the number of people attempting the perilous journey across the Channel by boat has decreased from about 250 in December to 90 last month. On the 18 February however, a boat carrying 34 people was intercepted off the coast of Dover.
With unseasonably mild weather and calm seas, coastguards believe the number of crossings may increase again, despite repeated warnings that migrants are risking their lives in the world’s busiest shipping lane.