Six people have been arrested in London for "suspected activity" linked to the proscribed Kurdistan Workers Party (PKK) as part of a "significant" counter-terrorism policing operation, police said on Wednesday.
Two women and four men were detained under the Terrorism Act 2000, the Metropolitan Police said, but there is "not believed" to be any imminent threat to the public linked to the probe.
The PKK is a separatist movement seeking an independent Kurdish state in southeast Turkey. It was banned under British law in 2001 and also considered a terrorist group in Turkey, the United States and the European Union.
"These are targeted arrests of those we suspect of being involved in terrorist activity linked to the group," said Helen Flanagan from the Met's Counter Terrorism Command.
As part of the investigation, raids were carried out at eight London addresses, including at a Kurdish Community Centre in north London.
"This investigation and activity is about protecting all of our communities, but particularly those in our Turkish and Kurdish communities," Flanagan added.
The PKK has been fighting a war Turkish state since its formation in 1978, resulting in the deaths of over 40,000 people.