A Briton has reportedly been arrested in Zambia over allegations he was involved in planning a US terror camp.
Haroon Rashid Aswat, of West Yorkshire, was held in the border town of Livingstone after entering the country from Zimbabwe, Zambian officials said.
The Foreign Office said it was seeking access to a British national reportedly in custody, but did not name him.
Counter-terrorism officials dismissed reports he was wanted for questioning over the 7 July London bombings.
Mr Aswat, 30, who is of Indian descent, is reportedly being held at the request of the American authorities, after being under US surveillance in South Africa.
James Ujaama pleaded guilty to involvement in the plot
They want to question him about a 1999 plot to set up an al-Qaeda training camp in Bly, Oregon.
James Ujaama, 38, a Muslim convert from Seattle who has lived in Britain, pleaded guilty to involvement in the plot in April 2003.
He faced up to 25 years in prison but received a two-year sentence after agreeing to co-operate in terrorism investigations until 2013.
Three US federal law enforcement officials said he was being questioned about Mr Aswat, who was referred to in the 2002 indictment of Ujaama by a federal grand jury in Seattle.
Sources told CNN the British authorities had denied a US request to capture Mr Aswat in the UK.