A man has been killed as at least 1,500 migrants tried to enter the Channel Tunnel in Calais on Tuesday night, French police have said, reports the BBC.
It came as David Cameron pledged that the UK government would do everything it could to combat the crisis.
Speaking as the UK confirmed an extra £7m funding for new fencing at the terminal, the prime minister said the situation was "very concerning".
More than 2,000 people tried to get into the terminal on Monday night.
The man who died on Tuesday night was Sudanese, aged between 25 and 30, according to the France Info website.
He is reported to have been hit by a lorry.
Speaking in Singapore, the prime minister said Home Secretary Theresa May would chair a meeting of the government's emergency committee, Cobra, about the crisis later.
"I have every sympathy with holidaymakers who are finding access to Calais difficult because of the disturbances there and we will do everything we can to work with the French to bring these things to a conclusion," Mr Cameron said.
"There's no point trying to point fingers of blame, it's about working with the French, putting in place these additional security measures, adding in the investment where that's needed - Britain will always come forward with that."
A Home Office spokesman said an additional £7m funding - outlined by the Home Secretary earlier this month - will pay for 1.2 miles of new fencing at the Eurotunnel site at Coquelles.
Work to put up fencing began earlier this month and was due to be completed this week, the Home Office added.