"The targets which were firstly bombed were by the help of Pakistani intelligence and the first batches of invading forces entered from Pakistan."
He also said that Iran's Shia had not given any assistance to the Taliban, a Sunni movement: "Iran has never adopted any Jihadi agenda while the leaders of Arab countries are just followers of America and Britain."
Dadullah also repeated his previous predictions that the Taliban were planning a large-scale spring offensive.
"Our readiness for next spring offensive is great and very huge as we precisely reconsider our previous strategy [in order that] we learn new effective fighting tactics and methods," he said.
"We have many suicide bombers for carrying [out] hundreds of suicide bombings during the coming spring offensive in Afghanistan."
However, he told Al Jazeera that he would not discuss the Taliban's plans with the media.
"We cannot talk about the new tactics to the media ... [they] must be kept secret," he said.
Dadullah also said that Muslims from around the world were keen to fight Christians and Jews in particular.
"No-one can know the number of mujahideen, as when it comes to fight Jews and Christians they are countless," he said.
|The Afghan government struggles to rule areas outside Kabul, the capital|
"Jihad is international, as we have Mujahideen from all over the world as Muslims across the world are supporting us and will stay with us in the future.
"The number of Mujahideen who are ready to fight might reach 6,000 or 10,000, but when the convoys of our enemy arrive all people fight, thus the number will reach 20,000.
"The suicide bombers are not included as we have thousands in each village and town who are ready to carry our suicide attacks. But those registered who joined training centres are 1,800 fighters.
Dadullah, who joined the Taliban soon after the movement was founded by Mullah Omar, also said that the Taliban now controlled large parts of Afghanistan.
"Taliban is not like that in the past, as we are now in control of most areas in Afghanistan.
"We will defeat the Americans and their allies. In return for each 20 soldiers we have killed, we lost one fighter."