Afghan intelligence agents say they have arrested a leading spokesman for the Taleban near the Pakistan border.
Mullah Omar (C) and Taleban leaders are still at large
Intelligence service spokesman Sayed Ansari named him as Dr Muhammad Hanif, who has been speaking for Afghanistan's former rulers since October 2005.
Mr Ansari told the Associated Press the spokesman had been detained on Monday. He did not say where he is being held.
Dr Hanif's capture, if confirmed, would be a notable success for the Afghan government as it battles the Taleban.
The authorities say more than 4,000 people were killed in Afghanistan in 2006 as bombings by the Taleban and their allies and operations by Nato-led troops soared.
Mr Ansari said Dr Hanif had been detained in the border town of Towr Kham in Nangarhar province soon after entering Afghanistan from Pakistan.
Two others travelling with him were also apprehended.
The spokesman first gave his name as Abdulhaq Haqiq, Mr Ansari said.
"But during the investigations we discovered that he is Dr Hanif," he told AP. "He also confessed to it himself."
Dr Hanif has been highly active over the past year, regularly e-mailing news organisations with the Taleban's version of events in the east of the country.
A man called Qari Mohammad Yousuf has performed similar functions for the Taleban in the south.
The two men were appointed after the capture in Quetta, Pakistan, of former Taleban spokesman Latifullah Hakimi in October 2005.
Reuters quoted an unnamed Taleban official who confirmed that Dr Hanif had been caught.
"We got this information today after our fighters told us that they tried Hanif's phone number repeatedly but got no response," the official said by telephone.
"Our commanders in Nangarhar and sources in the Afghan government confirmed the arrest."