Authorities in the United Kingdom say they have arrested a Canadian man on suspicion of being a member of a terrorist group.

Metropolitan Police in London say counter-terrorism detectives arrested a 28-year-old Canadian national at Heathrow Airport on Tuesday.

Officials say the man had just arrived on a flight from Canada, and that the investigation was related to the arrest hours earlier of a man in east London.

Both men are accused of membership in a proscribed terrorist organization, which could carry a sentence of up to 14 years in prison, should charges be laid.

Currently the men are being held without a warrant, which can be done for a maximum of 48 hours according to the U.K. Terrorism Act.

In an email, Metropolitan Police say they are not naming the terrorism group as the investigation is ongoing, noting that they will only confirm the identity of the men arrested if they are charged with an offence.