A Swedish woman has been arrested at London's Gatwick Airport on suspicion of committing a terrorism offence.

Police said the 40-year-old suspect was arrested on Thursday afternoon after arriving in Britain on a flight from Italy.

The South East Counter Terrorism unit said she was later arrested under Section 41 of the Terrorism Act 2000 on suspicion of commission, preparation or instigation of acts of terrorism.

Her arrest is understood to be related to the Islamic State group.

She remains in police custody.