LONDON — A small boat carrying migrants capsized in the English Channel early on Wednesday, according to the British maritime authorities, setting off a major rescue operation involving Britain and France.
The condition of the passengers and the status of the boat was not yet known. Lifeboats and helicopters from the British Coast Guard have been involved in evacuating passengers from the scene of the accident, as well as a Royal Navy patrol boat, a French Navy helicopter and a French fishing boat.
There were unconfirmed reports of fatalities after several passengers were thrown into the sea. But the authorities declined to give details on the number of people involved or on the nature of the accident.
The British Maritime and Coastguard Agency said in a statement that it was coordinating a search and rescue response to an “incident involving a small boat off Kent, working with the Navy, Border Force, Kent Police and other partners.”
Volunteer lifeboats were dispatched from several locations along the Kent coastline, and the station in Dungeness confirmed that they were still trying to rescue people in the Channel by 9 a.m.
According to data from the Royal National Lifeboat Institution, their boats began to be launched into the Channel around 2 a.m. on Wednesday morning, though officials have yet to confirm when the boat in distress was first spotted.
A British Coast Guard spokesperson said that helicopters from Lydd and Lee-on-the-Solent, in southern England, and one from the French Navy were involved in the rescue and that a fishing vessel was also helping. “South East Coast Ambulance and Kent Police are working with us and an air ambulance has been sent,” the spokesperson added.
The accident came a day after Prime Minister Rishi Sunak announced plans to try to cut down on migrant crossings of the Channel. Mr. Sunak said Britain would seek to clear a huge backlog of asylum applications.
The number of people trying dangerous boat crossings has swelled in the past year, posing a political problem for the Conservative government. Mr. Sunak has put an emphasis on rejecting asylum claims from Albania, which has become one of the leading sources of migrants using the channel route.
“We have to stop the boats and this government will do what must be done,” Mr. Sunak said in a statement to Parliament on Tuesday.
Suella Braverman, the British home secretary and the minister responsible for the country’s immigration policies, said in a statement that she was aware of a “distressing incident in the Channel,” adding, “My heartfelt thoughts are with all those involved.”
Ms. Braverman has been the target of intense criticism by human rights groups for her harsh stance on those arriving by small boat in Britain, including her emphatic support for a program that would send asylum seekers who arrive by that means to Rwanda, in cental Africa. At one point, she said she “dreamed” of seeing the first flights take off.
The policy has been challenged in Britain’s courts, and so far no asylum seekers have been sent to the African nation.
Last month, Britain and France signed a new agreement to try to stem the crossings by small boats, with Britain agreeing to pay France 72.2 million euros, about $76.4 million, during 2022 and 2023 to increase patrols on northern French beaches.
The hazards of the boat crossings were starkly illustrated when an inflatable dingy carrying 30 people capsized in French territorial waters near Calais and Dunkirk in November 2021. Twenty-seven of the passengers were killed in the accident, the most serious since migrant groups began collecting data.
The incident on Wednesday comes as temperatures in Britain have dropped below freezing for several days in a row and as conditions in the Channel grow especially treacherous during the winter months.