Britain arrests two in terror probe

British police say they have detained two men for terrorism offences as they tried to leave the country, adding that the arrests are not linked to attacks in Paris.

Police said on Tuesday the men, aged 22 and 20, were arrested early on Sunday at Dover Eastern Docks, a ferry terminal in southeast England and a popular departure point for ships heading to the port city of Calais, France.

The men had been living in Hayes on the outskirts of west London and are currently in custody, said police, who declined to reveal their nationalities.

"I would firstly like to confirm these arrests are not linked to the Paris terrorist incidents and there is no immediate threat to the local community," said Ian Hunter, head of investigations of the South East Counter Terrorism Unit.

"These men were trying to leave the UK via Dover and were arrested following good work by Kent police officers at the port."

Britain has beefed up security at ports, transit hubs and other busy public areas after 129 people were killed in coordinated gun and bomb attacks in Paris on Friday.

Hundreds of Britons have left to join the Islamic State group in Syria and Iraq in recent months. Some have attempted to use ferries to make their way there to try to avoid detection.