Despite the funding and support Tehran has provided to the Taliban for years, Iranian leaders now appear to be backtracking on their relationship with the militants.
Iran, which shares a 900km-long border with Afghanistan, did not recognise the Taliban during their 1996–2001 stint in power.
But Tehran softened its stance towards the Sunni militants in recent times in the name of pragmatism with a steady stream of military support with the aim of undermining the previous Afghan government.
As recently as June, the Iranian regime was observed providing the Taliban with extensive military support, with Iranian troops appearing in battle alongside Taliban militants in western Afghanistan.
Afghan officials from the previous government regularly accused the Iranian regime of supporting the Taliban as a means to thwart dam construction in Afghanistan's western region, as part of an effort to ensure the flow of water into Iran.
The Taliban and Tehran were also seen as politically close.
Just a few months ago, a group of Taliban leaders were wined and dined in Tehran, where then-Foreign Minister Javad Zarif called them "brothers" and said they would always have a home in Iran.
That relationship, however, now appears to be in question after the Taliban swept to power in August.
Iran's Foreign Ministry, after several weeks of relative silence, in early September criticised the Taliban's assault on Panjshir, the last stronghold of resistance to the movement.
In another incident, Iranian forces apparently seized and shipped Afghan military equipment to Iran.
Iran has also yet to recognise the Taliban government and does not appear content now that it is in charge.
"A government belonging to only one ethnic or political group cannot solve Afghanistan's problems," Iranian President Ebrahim Raisi said on September 18, after the militants formed a government composed entirely of Taliban and belonging almost entirely to the Pashtun ethnic group.
Raisi called for a government with representation for all Afghans -- which would include groups linked to Iran's Islamic Revolutionary Guard Corps (IRGC).
The Iranian regime now feels threatened by the Taliban after the group took over Kabul last month, say some analysts.
"In recent days, Iranian leaders, unlike in the past who supported the Taliban, have spoken out against the group," said Muhammad Naadam Sarwari, an international affairs specialist based in Nimroz province.
"This change shows the country's dissatisfaction with the Taliban," Sarwari said.
"The Iranian government will press the Taliban to respond positively to its demands. It is now up to the Taliban whether they will keep themselves under the control of the Iranian regime or act independently," he said.
The Iranian regime's anger and distancing from the Taliban are the beginning of new interference in Afghanistan, predict some Afghans.
"The Iranian government has never been a friend of Afghanistan and instead has tried to weaken the country," said Niaz Muhammad Niazi, a resident of Qala-e-Naw, Badghis province.
"Our request of the Iranian government is to stop interfering in our country," Niazi said.
"It is enough that [Iranian leaders] prevented the development and prosperity of our country in the past 20 years; now please do not cause more wars and killings of innocent people," he said.
"Although the Iranian government has provided significant financial and military support to the Taliban in recent years, the Taliban's views and interests differ from those of the Iranian regime," Hasan Hakimi, a civil society activist in Ghor province, told Salaam Times.
"Disagreements and conflicts between the Iranian regime and the Taliban may lead to conflict between them in the future," he said.
"In recent years, the Iranian government has provided large sums of money and resources to the Taliban and other armed groups in order to prevent the construction of dams and infrastructure in Afghanistan," Hamza Baloch, a political analyst in Zaranj, Nimroz province, told Salaam Times.
"Now, if the Taliban continue to build dams, Iran will arm another group against them," Baloch said.
Regional powers like Iran or Russia could very well return to funding proxy groups to secure their interests, Niamatullah Ibrahimi, an Afghanistan scholar at Australia's La Trobe University, told AFP.
It is "a recipe for violent conflict or resistance by others", he said.
The lack of an inclusive government "creates opportunities for exploitation by regional powers who are not going to be happy with them [the Taliban]".
[Emran from Herat contributed to this report.]