Recent days have seen spectacular gains for the fearsome jihadists, as their drive towards Kabul continues apace. Key cities, including Kandahar, Herat and Mazar-i-Sharif, have fallen to the Islamic militants in a domino effect, leading to fears that the capital Kabul will soon be overrun. There are many who see the hand of Pakistan behind the Taliban's resurgence, leading to bitter recriminations levelled at Islamabad.

       Chris Alexander, a former Canadian diplomat and politician, accused Pakistan of using "brutal force" to impose a "military solution".

       "It is cruel, immoral & destructive to keep up the fiction of a Doha ‘peace process’ or the pretence of normal relations with Pakistan, while Afghans suffer in hell," he tweeted.

       "Pakistan is invading — imposing by brutal force the ‘military solution’ it said was unavailable."

       He added: "Anyone denying or omitting to condemn the fact of Pakistan’s invasion is now complicit.

       "Any leader making false promises of peace is exacerbating war.

       "Any state failing to take action under Chapter VII is undermining international peace & security. #SanctionPakistan"

       Shuvaloy Majumdar, a Foreign Policy Director and Munk Senior Fellow, wrote in reply to a tweet by US journalist Walter Shapiro: "The humanitarian thing to do is #SanctionPakistan for the atrocities they’ve sponsored in Afghanistan.

       "While the world fought 20 one-year wars, while corruption & intransigence denied Afghans their future, ISI’s terror masters maintained instability through proxy war. End it."

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       The Inter-Services Intelligence (ISI) is Pakistan's top intelligence agency and is believed to have close contacts to the Taliban leadership.

       Indian politician Shashi Tharoor branded the Islamists "a wholly owned ISI subsidiary" in an article for Project Syndicate.

       Pakistan has a long history of support for different factions within Afghanistan, that reaches back to at least the early 1970s.

       More pertinently, Islamabad offered logistical support and backing to the mujahidin fighting against the Soviet occupation during the 1980s.

       A former Pakistan Senator claimed that his country was "fully supporting" the Taliban in an interview with the BBC.

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       Afrasiab Khattak, a member of the Awami National Party (ANP), said: "The Taliban is in a way an instrument of Pakistan’s policy of strategic depth in Afghanistan.

       "I think Pakistan is very happy with the Taliban’s advances.

       "I mean to say Pakistani generals, as the civilian government has no role in shaping or executing this policy."

       Pakistan's Prime Minister, Imran Khan, has strenuously denied supporting the jihadists and said that his government was not taking sides in Afghanistan.