A Taliban spokesman told Afghan agents who captured him that the hard-line militia's chief Mullah Omar lives in Pakistan's southwestern city of Quetta protected by that country's powerful intelligence service.
Pakistan's interior minister on Wednesday called the claim "totally baseless."
Mohammad Hanif, a Taliban spokesman captured Monday near the border with Pakistan, made the comments during interrogation by Afghanistan's intelligence service, which distributed to reporters a video CD of what it said was his questioning.
"He lives in Quetta," Hanif says of Omar, as he sits in an oversized chair in a dimly lit room, as Afghan agents pepper him with questions. "He is protected by ISI," the 26-year old said in a quiet voice, referring to Pakistan's Inter-Services Intelligence agency.
President Hamid Karzai made similar allegation during an interview with The Associated Press last year, saying Omar lives in Quetta and is protected by Pakistan's security services.
But Pakistan's Interior Minister Aftab Khan Sherpao rejected the claim, saying "this is totally baseless."
"We have no information on the whereabouts of Mullah Omar. He is not living in Pakistan," he told the AP Wednesday.
Sherpao said the "Afghan intelligence has made contradictory statements since the arrest of this so-called spokesman of Taliban. We don't know who this person is, and from where he had been arrested."
A predecessor of Hanif, Mullah Hakim Latifi, was arrested in 2005 by Pakistani police in southwestern Baluchistan province.
In the CD recording of his interrogation, Hanif also alleges that the former head of Pakistan's intelligence service, Hamid Gul, was supporting Taliban militants in their fight against Afghan and foreign troops.
Sayed Ansari, the spokesman for Afghanistan's intelligence service, said Hanif's real name is Abdulhaq Haji Gulroz, and he is an Afghan from Nangarhar's Chaparhar district. Ansari said Hanif has been living in northwestern Pakistani city of Peshawar.
Ansari has given conflicting accounts of Hanif's arrest, saying Tuesday he was nabbed after crossing the border from Pakistan, but telling reporters Wednesday the arrest was made about 25 kilometers (15 miles) outside the Nangahar provincial capital of Jalalabad.
Another purported Taliban spokesman, Qari Yousef Ahmadi, confirmed Hanif's arrest in a phone call from an undisclosed location, but said that the Taliban's governing body have already appointed a new spokesman, Zadiullah Mujahid.
He said the arrest would not affect the Taliban's campaign.
Hanif used to convey alleged statements from Omar and comment on fighting in the north, center and east of the country.
Western and Afghan officials have claimed a number of recent successes against Taliban leaders.
On Tuesday, NATO-led troops and Afghan forces detained a prominent Taliban commander during a raid on a compound in southern Afghanistan, the alliance said.
The commander was the leader of the insurgents in Panjwayi district of neighboring Kandahar province, where last summer NATO troops waged their biggest ground offensive in the Western alliance's history, said NATO spokesman Squadron Leader Dave Marsh.
"This seizure of a Taliban commander once again shows that there is nowhere to hide for insurgent leaders," Marsh said.
The captured militant, whom NATO did not identify, had fled another recent offensive by Afghan and NATO forces in the south of the country, the alliance said. He was captured in the Gereshk district of Helmand province.
Last month, a U.S.-led coalition airstrike killed Mullah Akhtar Mohammad Osmani, a key associate of Omar and the highest-ranking Taliban leader killed by the U.S.-led coalition since the late 2001 invasion of Afghanistan that ousted the hard-line regime for hosting Al Qaeda leader Usama bin Laden.
Over the past year, the Taliban have launched a record number of attacks, and some 4,000 people have died in the insurgency-related violence, according to a tally by The Associated Press based on reports from Afghan, NATO and coalition officials.