Maulvi Fazlullah, the head of a Taliban faction in Pakistan's Swat Valley, was reportedly killed along with six of his comrades in the Barg Matal district of Afghanistan's Nuristan province, which lies close to the border with Pakistan, said Mohammad Zaman Mamozai, chief of the Afghan border force for the eastern region.
"Maulvi Fazlullah was killed in direct clash with Afghan border police...last night," he said.
He did not have further details. The Afghan Taliban have confirmed the fighting, but insist no foreign militants were involved.
The news of Fazlullah's death comes after reports of several days of clashes between Afghan forces and militants in Barg Matal.
Maulvi Faqir Mohammad, who heads a Pakistani Taliban faction based in the Bajuar tribal region, denied media reports that Fazlullah was leading any assault in Afghanistan.
"He could be in Nuristan because the Taliban have been moving back and fourth along the (Pakistan-Afghan) border," he told Reuters by telephone prior to reports of Fazlullah's death.
"He may be living in Nuristan but he is not engaged in any fighting there," he said.