Migrants in Calais have taken part in a protest asking for human rights protection amid rising tensions at the French port.
There is an increased police presence in the town after dozens of migrants tried to storm a ferry bound for Dover.
Police are giving drivers guidance to avoid unwittingly taking on migrants as some seeking to enter the UK have attempted to jump into vehicles.
A large influx of migrants has arrived at Calais in recent months.
Earlier this week scores of illegal migrants tried to run up the main ramp of a ferry bound for the UK, but were foiled when the crew raised the ramp and turned a fire hose on them. They were later detained by French police.
Mayor of Calais Natacha Bouchart has threatened to blockade the port unless the UK helps to control the number of migrants, claiming the town has been “taken hostage” by more than 1,000 migrants who want to cross the channel.
Many of the migrants are from African countries, including Somalia, Sudan and Eritrea, while others have fled from the conflict in Syria. It has been reported that clashes have erupted between rival African migrants.
At the scene: Duncan Crawford, BBC News in Calais
“We will continue until the end. Human rights for all,” said one banner held aloft by some of the migrants. “Stop beating us,” stated another.
About 200 had gathered in Calais to protest and make their voices heard. Police officers watched on as they marched through the streets.
Many of the migrants are from East Africa, from places like Sudan and Eritrea. Almost all say they left their homes to escape poverty or persecution.
Noreldin, 30, from Darfur, Sudan, told me he paid people smugglers 1,000 euros to go by boat from Libya to Italy, before arriving in Calais last month. Now he spends his days trying to reach Britain.
“Sometimes I try under the truck, sometimes inside the truck,” he says.
He adds that he’s already risked his life seven times trying to smuggle himself across the Channel. There are many more like him.
‘Migration no crime’
The protesters who took to the streets handed out a statement to journalists signed “the migrant communities in Calais”.
It read: “Migration is not a crime and each and every one of us has reasons why we had to leave our countries and our families and why we are here now.
“Europe is always talking about human rights and freedom but we cannot find this here.
“This is why we want to demonstrate and bring our demands on the streets.”
Three men were arrested on Friday on suspicion of illegal entry to the UK, Kent Police Roads Policing Unit said.
One man was found clinging onto the bottom of a mobile home on the M20 motorway and was later handed over to the Home Office.
Two other men were later detained having been found under another mobile home, the unit said.
A worker at a migrants’ charity clothes shop called on UK Prime Minister David Cameron to offer help to the migrants, saying they were becoming overwhelmed by the situation.
Volunteer Pascal Froehly said: “I have seen men women and children sleeping in the snow. I have seen people running on lorries. It’s scandalous.”
He added: “This is Europe. You call yourself civilised and you allow women and children to walk around unprotected on the street. It’s that bad.”
In 2002 the French government closed the main Red Cross centre at Sangatte near Calais, but insanitary illegal camps have constantly sprung up in its place since then.
In recent months French police have tried to break up the camps, but the migrants say they have nowhere else to go. They can often be seen sheltering under plastic bags and sheets, with many depending on charities for food.
UK Deputy Prime Minister Nick Clegg said on Thursday that Home Secretary Theresa May had been in touch with the French government on the issue and added: “We will do whatever is needed with the French authorities to make sure that our border is safe.”