The Afghan Taliban are believed to have captured a top Islamic State (Isis) commander, who was recruiting for the Iraqi extremist group, and 45 other militants for involvement in "anti-Islamic activities".

The Afghan militants, formally known as the Islamic Emirate of Afghanistan, apprehended Mullah Abdul Rauf Khadim in the Kajaki district of southern Helmand province, according to the Pajhwok Afghan News.

Khadim, who once fought with the Taliban, awaits judgment along with 45 supporters.

"Mullah Khadim, who claims allegiance to Daesh [Arabic acronym for IS] forcibly assembled local residents on Thursday last in the Kakaji's Azan area and told the people that Mullah Omar no longer exists and they should now support him," said Abdul Ahad Masoomi, a tribal leader in Kajaki district, adding that sharp differences between Khadim and the Taliban commanders led to the extreme step.

The Afghan Taliban is yet to officially comment on the matter.

Meanwhile, IS leader Abu Bakr al-Baghdadi has reportedly poured scorn on Afghan Taliban leader Mullah Omar, calling him "demented".

An unverified statement attributed to al-Baghdadi read: "Mullah Omar does not deserve any spiritual or political credibility. The organisation has achieved in two years what Taliban could not achieve in its campaign in 10 years."

Earlier, Pakistan Taliban (TTP), which operates independently from the Afghan organisation, seemingly pledged allegiance to IS, which has seized swathe of territories in Iraq and Syria. However, the TTP's spokesperson Shahidullah Shahid was fired immediately for the announcement, with a clarification that the group does not want to operate with IS.