Taliban officials say a Sunday Expressreporter has been arrested trying to enter Afghanistan illegally.
The Pakistan-based Afghan Islamic Presssaid the journalist has been identified as Ms Yvonne Ridley.
She was apparently dressed in Afghan clothes and her head was swathed in a scarf.
The AIP quoted a Taliban spokesman as saying Ms Ridley and two Afghan guides were arrested near Jalalabad.
A spokeswoman for the Express Newspapershas confirmed the arrest.
Sunday Expresseditor Mr Martin Townsend said: "We are seeking an urgent clarification of the exact position and are co-operating fully with the Foreign Office in securing the quick and safe release of our journalist."
The agency quoted Taliban authorities as saying the woman was not carrying a passport nor any other travel documents. A spokesman for the British High Commission in Islamabad, the Pakistan capital, said he has no information on the report.
She has been writing stories for both the Sunday Expressand Daily Expressnewspapers from the Pakistani cities of Peshawar and Islamabad.
Ms Ridley, from Stanley, Co Durham, is a former assistant editor of the Sunday Sunbased in Newcastle.
A spokesperson for the Sunday Expresssaid later: "We are working closely with the Foreign Office to ascertain the exact circumstances surrounding the arrest of Yvonne Ridley. Yvonne is The Sunday Express's chief reporter and is a highly experienced journalist who has worked in many countries around the world.
"She volunteered for this assignment and filed an outstanding and exclusive despatch for the Sunday Expresslast week. Everyone at Northern and Shell and Express Newspapers is deeply concerned and anxious for her speedy and safe return."
PA