Ubaid Allah, a former Taliban defence minister regarded as an associate of the elusive Taliban leader Mullah Muhammad Umar, is alleged to have made the statement via satellite phone from an undisclosed location.
"Bad weather is the reason for the reduction in attacks," he said.
"We will step up attacks as the weather changes. The Taliban movement is active under the leadership of Mullah Muhammad Umar. And Taliban will fight till the last Talib is alive."
However, a group of former Taliban fighters are said to have embraced a US-backed reconciliation drive, while the US military says that, three years after the Taliban government fell, fighting is waning.
Ongoing military operations
The US military continues to conduct operations despite heavy snow but has reported little fighting. US spokesman Major Steve Wollman said the bad weather had slowed forces down but had not stopped them.
"Helicopters give us a great advantage to get over snow-covered roads," he said.
US and Afghan officials insist that many Taliban members have signalled their readiness to make peace and joined in a planned reconciliation process. However, it remains unclear if figures with influence over those still fighting have come forward.
Abd al-Hakim Mujahid, the former Taliban ambassador to the United Nations, said in Pakistan on Sunday that he had just returned from Kabul where he met President Hamid Karzai.
Mujahid said his delegation represented Khudamul Furqan Jamiat (Association of the Servants of Quran), a group which merged with the Taliban but broke away again in December 2001.
Former Afghan president
Burhan al-Din Rabbani
He said he was accompanied by Arsala Rahmani, former deputy minister of higher education, Rahmat Allah Wahidyar, former deputy minister of refugees, and Qazi Habib Allah Fawzi, once the first secretary at the Afghan embassy in Pakistan.
"We have influence in Afghanistan as we have worked in the governments of Burhan al-Din Rabbani and Taliban," Mujahid said. "Now we want to work with this government." Rabbani is a former president of Afghanistan.
Presidential spokesman Khaliq Ahmad said there was progress in the reconciliation programme but could not confirm Mujahid's account.
No to talks
Meanwhile Ubaid Allah claimed no Taliban representatives had held talks with the invading US forces.
"We consider jihad is the only way to force them to leave our country," he said. "We will fight with them. Dialogue is not a solution."
In a separate telephone interview, Mullah Hakim Latifi, a purported spokesman for the militia, said individual Taliban commanders may ally with the government, but insisted Mullah Umar and his key lieutenants would carry on the fight.