The Afghan Taliban's political chief in Qatar, Syed Tayyab Agha, resigned on Tuesday after criticising the election process that led to the appoinment of the group's new leader, Mullah Akhtar Mansour.
Mansour was announced as the new leader of the Taliban after the death of former leader Mullah Omar was confirmed last week.
Several members of the group have reportedly complained about the election process, saying they were not consulted.
Tayyab Agha served as Mullah Omar's personal secretary before heading the Taliban's political office in Qatar.
He said he resigned to avoid "expected future disputes" and the group should not allow foreign interference, the BBC reported.
Reports have suggested that Mullah Mansour was chosen by "pro-Pakistani circles of the group" and Tayyab Agha's words have been seen as a sign of a growing rift over the new leader's appointment in the Taliban.
The family of Mullah Omar has also rejected the appointment of his successor Mullah Mansour.
At least one faction is reportedly backing Mullah Omar’s son Yaqoob to take over after his father and there have been calls to allow a council of Islamic scholars "and those mujahideen [fighters] who had laid down the base of the Emirate of Afghanistan through their sacrifices" to appoint the group’s new chief.
Both Omar’s brother Abdul Manan and his son Yaqoob were among dozens of Taliban members who walked out of a council meeting on Wednesday in the western Pakistani city of Quetta after Taliban commanders decided on the group’s new leader, Reuters reported, citing three attendees.
Shortly after Mansour’s appointment, the BBC quoted Mullah Abdul Manan Niazi - a senior member of the Taliban’s Supreme Council also from the Quetta Shura - rejecting Mansour’s selection as a breach of the group’s rules.
"According to Islamic rule and principles, when a leader dies, a Shura [council] is called, then its leader is appointed," Mullah Niazi said.
The Taliban's former Kandahar Province governor, Mullah Mohammad Hassan Rahmani, has also rejected Mansour’s leadership, telling Radio Free Afghanistan that he was chosen by a small clique of Taliban seniors despite being opposed by other Taliban leaders including Mullah Abdul Razzaq and ex-Guantanamo detainee Mullah Abdul Qayyum Zakir.
On the other hand, Mullah Zakir, who is based in Afghanistan’s Helmand province and is a member of the Leadership Council of the self-proclaimed Islamic Emirate of Afghanistan, brushed off reports that his Taliban faction was opposed to Mullah Mansour’s leadership in a statement on the Taliban’s official website.
The leader of the Taliban’s Haqqani network, Jalaluddin Haqqani, who just days ago was reported dead, seemingly came out to refute news about his death with a new statement published on Taliban websites in which he swore his allegiance to Mullah Mansour.
Mullah Mansour released an audio message on Saturday calling on all the factions of the militant group to maintain their unity in their fight against the Western-backed Afghan government.
Mansour, who like his predecessor is said to be in favour of the Taliban’s peace talks with the Afghan government, is expected to push for the continuation of talks into a second round after a first round of talks was completed in early July.
However, the Taliban has denied reports that a second round of talks is being planned to be held in Pakistan or China, with Mansour himself saying that such rumours are "propaganda campaigns by the enemy."