British police are questioning five people detained under anti-terrorism laws after police found a number of weapons in their possession.
Authorities say the detentions of the three men and two women follow a raid Friday on a home in the southwestern British city of Plymouth.
Officers confiscated a number of weapons, suspected imitation weapons, other suspicious devices and materials related to what authorities described as "political ideology." But officials say the investigation is not linked to any religious group.
Authorities identified the five as British nationals and said three of them face drug charges. News media reports say authorities believe the five were planning to take part in protests in London during the Group of 20 economic summit in the British capital Thursday.
Security is reported extremely tight in the city with thousands of officers taking part.
Some information for this report was provided by AFP and Reuters.