Censor.NET reports citing Telegraph.
The alarm was raised by the coastguard after a 28ft yacht was reported to have run aground on mud at the mouth of the Rover Ore near Orford, Suffolk.
It follows warnings that the east coast of England is particularly vulnerable to small boats of immigrants trying to enter the country illegally.
All weather and inshore lifeboats were sent to the scene and seven Ukranians were reportedly found on the boat.
The yacht was towed to Orford where the group were detained by UK Border Force officials.
The seven were being held in custody on Sunday night on suspicion of immigration offences.
A spokesman for the RNLI said: "On arrival at scene, the ILB (inshore lifeboat) crew discovered that the yacht was inside the river mouth and was in danger of running aground again, after it had initially managed to refloat.
"Communication was difficult due to language barriers, but a tow was eventually secured and it was taken to Orford Quay.
"The yacht was handed into the care of HM Coastguard Shingle Street, in addition to the Border Agency."