The chief of al Qaeda's Syria affiliate described the rival Islamic State group's self-proclaimed caliphate as "illegitimate", in a wide-ranging television interview aired on Wednesday.
In the second part of his appearance on the Qatari-owned Al-Jazeera news channel, al Nusra Front leader Abu Mohamed al-Jolani criticised IS at length and said he did not foresee a reconciliation between the two jihadist groups soon.
"They announced a caliphate, but the scholars rejected it as illegitimate. It is not based on Islamic law," Jolani said, his face hidden from view by a black scarf.
The rivalry between the two groups deepened after IS declared a caliphate spanning across Syria and Iraq in June 2014.
This conflict, Jolani said, had seen IS kill more than 700 members of Al-Nusra in a single battle, as well as women and children.
"There is no indication of a solution between us and them at this time. We hope that they repent and return to the Sunni people," Jolani said, adding that the rivalry had allowed the Syrian regime "to flourish."
He refused to call IS fighters "infidels" -- a term usually referring to non-Muslims -- but instead said they had strayed from the path of Islam.
"They did not commit to the orders we had... including not blowing up markets or killing people in mosques," he said.
Jolani also criticised IS for not "being serious in fighting the regime" of Syrian President Bashar al-Assad.
'Rising up against hegemony'
When asked by Al-Jazeera interviewer Ahmad Mansur about Al-Nusra's ties to al Qaeda and whether a split was possible, the jihadist leader refrained from answering directly.
"The issue is not about leaving al Qaeda. It is about who rises up against hegemony," said Jolani, who said he had fought in Iraq against American forces.
As with the first installment of the interview aired last week, an "al Qaeda in the Levant" flag featured prominently on the table in front of Jolani.
He said as many as 30 percent of Al-Nusra's members were foreigners, including "a small number of Americans."
His television interview comes on the heels of several major victories for Al-Nusra against regime forces in Syria's northwest Idlib province.
In recent months, a Nusra-led alliance has seized several major government posts there, including the provincial capital.
Mansur hinted that the interview had taken place in the province, saying the pair were currently in "liberated lands in northern Syria."
As in the first interview, Jolani again rejected political solutions to Syria's four-year war, saying an end to the crisis could only come through "jihad", or holy war.
He also spoke about regional developments in Iraq and Yemen, accusing Iran of seeking to expand its "empire" in the Middle East.
"We will cut off the hands of Iran in the region," he threatened.
Last week, the jihadist chief had said his group would be willing to protect Syria's minorities if they renounced Assad and "came into the bosom of Islam."
He also said he had received orders from al Qaeda's central command not to attack the West.
"Our mission in Syria is the downfall of the regime, its symbols, and its allies, like Hezbollah," Jolani said, referring to the powerful Shiite movement fighting alongside the Bashar al-Assad regime.