“Several migrants lost their lives,” the Pas-de-Calais prefecture said, without specifying the number of victims, AFP reported.
Regional prefect Jacques Billant is set to hold a news conference at 10:00 am (0800 GMT), his office said.
Maritime authorities said Saturday that numerous attempts by migrants to make the perilous crossing in small boats have been attempted in recent days, with 200 people rescued in 24 hours over Friday and Saturday alone.
At least 12 migrants died off the northern French coast when their boat carrying dozens of people capsized this month.
It was the deadliest such disaster this year, which had already seen 25 people die in migrant crossings, up from 12 in 2023.
The French and British governments have sought for years to stop the flow of migrants, who pay smugglers thousands of euros per head for the passage to England from France aboard small boats.
More than 22,000 migrants have arrived in England by crossing the Channel since the beginning of this year, according to British officials.