Al-Qaeda leader Ayman al-Zawahiri pledged the group's allegiance to new Taliban chief Mullah Akhtar Mansour in an audio recording released today on jihadist websites.
"As emir of Al-Qaeda, I pledge to you our allegiance, following the path of Sheikh (Osama) bin Laden and his martyred brothers in their allegiance to Mullah Omar," Zawahiri said, referring to the former Al-Qaeda leader and to the longtime Taliban chief whose death was confirmed last month.
The statement came amid a bitter struggle within the Taliban over Mansour's leadership.
The recording was featured in a video that opens with images of bin Laden - who was killed by US special forces in Pakistan in 2011 - pledging allegiance to Omar.
The recording then plays over a picture of Zawahiri, who is believed to be in hiding in the Afghanistan-Pakistan border region.
He says that the "Islamic emirate" established by the Taliban in Afghanistan was the "first legitimate emirate after the fall of the Ottoman Empire, and there is no legitimate emirate in the world apart from it."
He pledged to Mansour to "implement sharia law" and to continue "jihad until every part of occupied Muslim land is free."
Mansour was announced as the new Taliban chief on July 31, after the movement confirmed the death of Omar, who led Islamist insurgency for some 20 years.
But splits have emerged in the Taliban following the appointment, with some top leaders, including Omar's son and brother, refusing to pledge allegiance to Mansour.
Zawahiri's pledge also comes as Al-Qaeda faces a growing rivalry with the Islamic State group, which has seized control of larges parts of Syria and Iraq, for preeminence in the global jihadist movement.