Anti-migrant protesters have clashed with police and blocked a dual carriageway.
Rival groups have assembled in Dover to demonstrate over the arrival of thousands of migrants in small boats.
Traffic on the A20 was at a standstill in both directions after protesters assembled on the road in large numbers.
At one point several officers were seen restraining a person on the ground.
The individual was later arrested, police told the PA new agency.
There have been other sporadic clashes with the group of at least 50 police officers by the A20.
It is thought that groups from across the country have travelled to Dover.
A heavy police presence was also in place in the town, with a large concentration of officers in Market Square, where pro-migrant activists made their stand.
He continued: “We are not those people. We are standing up and welcoming people who are in desperate circumstances fleeing from awful situations.”
Officers on horseback were among those monitoring the situation.
