Three British men are being held in Taliban custody in Afghanistan, UK non-profit group the Presidium Network said on Saturday.
The group said on Twitter it had been "working closely with two of the families."
According to Sky News, so-called "danger tourist" Miles Routledge was among those detained.
The other two men are charity medic Kevin Cornwell and another unidentified UK national who manages a hotel in Kabul, the report said.
"We are working hard to secure consular contact with British nationals detained in Afghanistan and we are supporting families," a spokesperson for Britain's Foreign, Commonwealth and Development Office (FCDO) told Reuters in a statement, but did not confirm the details of the British nationals.
Routledge, 23, has gained fame, and attracted controversy, by traveling to dangerous countries and posting about it online.