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PESHAWAR, Pakistan — A dissident faction of the Afghan Taliban said negotiations with new militant leader Mullah Akhtar Mohammad Mansoor had failed, a development that is likely to split the armed network in two.

The militant group had been in disagreement over who should succeed former supremo Mullah Omar, whose death was announced in July.

"The demands were very simple. We wanted him to step down and let the Supreme Council appoint the successor to Mullah Omar by consensus."

Mansoor, the Taliban’s former aviation minister, told his commanders that Omar had died two years ago and declared himself the new Taliban leader. He said Taliban's supreme decision-making body “Rahbari Shura,” or Supreme Council, had appointed him as the new leader. Others didn’t believe it and opposed his ascension.

It triggered widespread ‎differences within the militant network and many senior Taliban commanders refused to accept Mansoor as leader or work under his command. The Taliban later formed a council of prominent religious scholars, the Ulema Council, to resolve differences between the two rival factions.

A spokesman for the anti-Mansoor faction said their talks failed on Saturday after ‎Mansoor told the Ulema Council that he would not accept any demands of the rival group.

"We and our people remained silent for two months and wanted the Ulema Council to peacefully resolve our differences, but Mullah Mansoor has told the Ulema Council he would not accept our ‎demands," Mullah Manan Niazi, a spokesman for the anti-Mullah Mansoor faction, told NBC News.

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Former Afghan Taliban leader Mullah Omar (left), and Mullah Mansoor. Afghan Taliban via EPA

"The demands were very simple. We wanted him to step down and let the Supreme Council appoint the successor to Mullah Omar by consensus."

Niazi said they would now launch their own militant operations against U.S.-led foreign forces and the Afghan government and its armed forces in Afghanistan.

"We don't want the Islamic Emirate to break as thousands of mujahideen had sacrificed their lives for establishing it,” he said.

He added: “We would announce that working under Mansoor's leadership isn't a jihad. He hasn't been appointed leader of the Islamic Emirate of Afghanistan by consensus, therefore ‎we would now publicly oppose him."

Related: Taliban Commanders Unite Behind New Leader

The dissident commanders had aligned behind Omar’s son and brother, who had earlier opposed Mansoor’s appointment. However, Niazi said the pair joined Mansoor’s faction after being placed under financial pressure.

"Both of them were not prominent among the Taliban fighters, but we supported them and wanted to get united all the divided Taliban factions through them, as they belonged to Mullah Omar's family," Niazi said. "However they left us alone and joined our rival faction, headed by Mullah Mansoor."

Related: 'Culture of Guns' Drives Afghan Violence

He alleged that Omar's younger brother, Mullah Abdul ‎Manan, had been receiving money meant for the Islamic Emirate, but Mansoor threatened to stop the flow of funds if he didn't announce his support.

‎Niazi said several senior members of the Leadership Council and commanders still opposed Mansoor and would soon announce their own operations inside Afghanistan.

Asked if they would launch a separate faction other than the Islamic Emirate run by Mansoor, Niazi said they had founded the Islamic Emirate and are its "real heirs."

"We and our people rendered many sacrifices for the Islamic Emirate," he said.