A number of migrants have been intercepted as they tried to cross the English Channel to reach the UK.
The Home Office said Border Force had been dealing “with a number of ongoing small boat incidents” off Kent, but has not yet confirmed any figures.
The Coastguard said it had been co-ordinating a search and rescue since the early hours, with Dover and Dungeness lifeboats attending.
On Friday, boats carrying an estimated 140 migrants were intercepted.
It is thought another 80 people were detained on Saturday.
The Home Office has been approached for comment.
In the early hours of Saturday, French authorities were alerted to a migrant boat and intercepted 16 migrants.
They included five women and a child, and were taken to Dunkirk.
On Sunday and Monday more than 130 suspected migrants were stopped as they attempted to reach the UK from France.
Home Secretary Priti Patel has acknowledged that a recent increase in the number of migrant boats making the dangerous crossing is linked to the Covid-19 lockdown.
Since lockdown was announced in Britain on 23 March, at least 609 migrants have been intercepted by UK authorities and brought ashore.
Clare Moseley, from aid group Care4Calais, said it was “little wonder” those living in French refugee camps were “desperate to make this dangerous crossing, given the awful conditions they face”.
“Coronavirus has made a bad situation life-threateningly worse,” she said.
“These people are fleeing terrifying situations in some of the most dangerous parts of the world. They aim for the UK because they want to be safe.
“Many have family or other connections, and others know our language and want to integrate and contribute,” she said.