The authorities in Pakistan say they have arrested leading Taleban spokesman Latifullah Hakimi.
The Taleban were driven from power by a US-led assault in 2001
"Our security forces captured him today, and he is in our custody," said Interior Minister Aftab Khan Sherpao.
Mr Hakimi has spoken regularly on behalf of the Taleban, who US-led forces drove from power in Afghanistan after the 11 September, 2001 attacks.
Pakistan Information Minister Sheikh Rashid Ahmed said he was detained in Balochistan province.
The Taleban oppose the US-backed government of President Hamid Karzai in Kabul.
They have been blamed for a wave of attacks, mainly in the south and east of Afghanistan this year.
Mr Karzai's government has frequently accused Pakistan of not doing enough to curb incursions by Taleban fighters and other militants, which it says are based on Pakistani soil.
Islamabad denies the allegations.
Pakistan's authorities publicly withdrew their support for the Taleban after the ruling Afghan militia were ousted four years ago, but Pakistan's Western allies have accused it of not severing ties completely.
The BBC's Barbara Plett in Islamabad says Mr Hakimi's arrest is being seen as a message that Islamabad is doing whatever it can.
She says analysts see this as a bigger blow to the Taleban than the capture of many of its military commanders, because Latifullah Hakimi was regarded as the voice of the group.
Mr Hakimi's exact ties to the Taleban have not been verified, but according to Afghan and US officials quoted by the Associated Press news agency, he is believed to represent factions within the rebel group.
He was a key contact for journalists seeking to establish whether or not the Taleban had carried out particular attacks in Afghanistan.
He usually spoke by satellite phone, occasionally switching to mobile phones registered in Afghanistan or Pakistan.
He last spoke to the BBC on Thursday, telling Rahimullah Yusufzai in Peshawar that a blast that killed 12 people near an army base in Kabul last week was caused by a Taleban suicide bomber.
Mr Sherpao told private Pakistani TV station, Geo, that Mr Hakimi's capture is a "big success" for the law enforcement agencies.
A spokesman for President Karzai said he hoped the arrest would lead to other Taleban leaders being detained.
"We are grateful for the arrest of Hakimi by the Pakistani government. He was a person who claimed the lives of many innocent people like clerics, doctors, teachers," the spokesman, Khaliq Ahmed Khaliq, told the BBC.