Six British citizens held in northern China are expected to be deported soon, UK diplomats in Beijing have said.
They are among 11 Britons, including two with dual British-South African nationality, who have been arrested. It is not clear why they are being held.
The Britons are part of a group of 20 foreigners detained in Inner Mongolia on 10 July.
African charity Gift of the Givers said they were tourists but China had linked some to a terror group.
Gift of the Givers said on Facebook that the group, comprising South Africans, Britons, and one Indian citizen, had been arrested when they landed at Ordos airport.
It said: “The Chinese… suggested that some members were linked to a terror group, to a banned organisation, to watching propaganda videos in their hotel room.”
The charity said the group included some doctors and businessmen, and none had terror links.
The BBC’s Martin Patience in Beijing says there has been no official word from the Chinese authorities on why the tourists were arrested.
UK officials have said they are “seeking further clarification” on the reason for the arrests, and that consular staff have visited the group to provide assistance.
Gift of the Givers said South African and British officials had met Chinese foreign ministry authorities on Tuesday.
News of the arrests comes as Beijing hosts South Africa’s Deputy President Cyril Ramaphosa, who met China’s Premier Li Keqiang and Vice President Li Yuanchao on Tuesday.
Mr Ramaphosa arrived on Sunday for his five-day visit.