Afghan officials say clashes between two Taliban factions have killed dozens of militants in the country's west, underlying divisions in the militant group that has waged a deadly 17-year insurgency against the Western-backed government in Kabul.

Jilani Farhad, the spokesman for the governor of Herat Province, said at least 28 Taliban fighters were killed and 25 wounded in the Shindand district, near the border with Iran, on November 30.

Hekmatullah Hekmat, the district's head, said the clashes pitted fighters loyal to Taliban leader Mullah Haibatullah Akhundzada against forces allied with Mullah Mohammad Rasul, a former militant commander who leads a breakaway faction in western Afghanistan.

Mullah Rasul's faction has been engaged in deadly clashes with fighters from the mainstream Taliban in southern and western Afghanistan since 2015, leaving scores dead on both sides.

In October 2017, at least 40 Taliban militants from the warring sides were killed in clashes in Shindand district.

In June 2017, a Taliban suicide bomber riding a vehicle packed with explosives targeted supporters of Mullah Rasul in the southern province of Helmand, killing four fighters.

Mullah Rasul's group is active in the provinces of Herat, Farah, Nimroz, and Helmand and is believed to be fighting the mainstream Taliban for control of drug-smuggling routes.

Mullah Rasul is believed to receive arms and support from Afghan intelligence, which has attempted to divide the militant group.

Mullah Rasul, who was believed to have been close to Taliban founder Mullah Mohammad Omar, served as the governor of southwestern Nimroz Province during the group's rule from 1996-2001.

Mullah Rasul has expressed willingness to reach a peace deal with Kabul, unlike the mainstream group, which has rejected calls for talks with what it considers a puppet government.

The Taliban announced the death of Mullah Omar in 2015. But the Afghan government said Mullah Omar had died in the Pakistani port city of Karachi two years earlier.

Some Taliban commanders like Mullah Rasul accused the leadership of covering up Mullah Omar's death and have not recognized subsequent leaders.

With reporting by Tolo News and Khaama