The UK coastguard has said it is responding to "multiple incidents" involving small boats in the Channel.
HM Coastguard said Border Force and RNLI vessels had been deployed as part of the response.
It comes hours after Sir Keir Starmer and French President Emmanuel Macron announced a deal they said was designed to crack down on small boats.
The number of crossings tends to be higher when the weather in the Channel is calm, as it was on Friday morning.
At least 21,000 people have already made the journey since January, putting 2025 on course to be a record year for crossings.
The latest Home Office figures show 573 people made the crossing in 10 boats on Thursday.
According to the Red Cross, many people cross the English Channel in the hopes of finding and joining family who have already made it to the UK.
It says people are often separated from their loved ones as they flee their homes or on their journey in search of safety, which can take many years.
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Why do so many from around the world try to cross the English Channel?
Channel crossings rise 50% in first six months of 2025
The UK hosts less than 1% of the world's refugees, with 71% seeking safety in neighbouring countries to their own. For example, the Red Cross says Jordan currently hosts 1.3 million refugees from neighbouring Syria.
Many of those seeking refuge in the UK rather than other European countries do so because they can speak English.
Under the terms of the "one in, one out" scheme agreed between the UK and France, people who cross the Channel will be returned to France each week in exchange for the same number of asylum seekers who have been accepted to come to the UK.
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Speaking next to France's President Emmanuel Macron at a news conference in north west London, UK Prime Minister Sir Keir Starmer said it would come into force in a matter of "weeks".
"Migrants arriving via small boat will be detained and returned to France in short order," he said.
"In exchange for every return, a different individual will be allowed to come here via a safe route - controlled and legal - subject to strict security checks, and only open to those who have not tried to enter the UK illegally."
The prime minister said the arrangement would begin as a "pilot", with reports suggesting that just 50 people per week will be sent to France back across the Channel.
However, neither Mr Macron nor Sir Keir mentioned any figures in the news conference.
(c) Sky News 2025: Coastguard responding to 'multiple incidents' involving small boats in Channel
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