Pakistan’s Foreign Minister Shah Mehmood Qureshi on Monday said the international community needed to look into the failures of Afghan security forces in the face of Taliban offensives across Afghanistan, Reuters reported. 

Taliban fighters have swiftly gained territory across Afghanistan since May, including six provincial capitals in the last three days, as international forces near a complete withdrawal from the country after 20 years of fighting. 

"The capacity-building, the training, the equipment... where is it?" Qureshi said at a news conference quoted by Reuters. 

Pakistan cannot be held responsible for the failure of others, he further said. 

Kabul and several western governments said Pakistan's support for the Taliban allowed it to weather 20 years of war after being pushed from power in 2001 by a US-led invasion of Afghanistan, the report said. 

The group today controls more territory than that at any point since 2001. 

Pakistan denies supporting the Taliban. Qureshi said Islamabad was not taking sides in Afghanistan. 

"The lack of will to fight, the capitulation that we are seeing in Afghanistan... can we be held responsible for that? No, we cannot," Qureshi said, adding that Pakistan supported a political solution to bring peace to Afghanistan. 

Qureshi said Islamabad was concerned at the violence and the lack of progress in peace talks between the Taliban and the Afghan government, saying that Pakistan had most to lose from an unstable Afghanistan as a direct neighbor. 

A protracted war in Afghanistan is Pakistan's “nightmare scenario,” the country's national security advisor to Prime Minister Imran Khan said on Monday, according to an AP report. 

Moeed Yusuf said Pakistan is pushing the Taliban to return to negotiations, but its leverage is waning as the insurgent group gains more ground in Afghanistan. 

Yusuf also attacked the performance of Afghanistan's National Defense and Security Forces, claiming over a trillion dollars was put into Afghanistan: "What is going on with this well-equipped and trained force?”

In their sweep through Afghanistan, which began with the late April start of the final withdrawal of US and NATO troops, the Taliban have gained control of strategic and lucrative border crossings, including the Spin Boldak crossing with Pakistan. 

Last weekend the Taliban closed it, after Islamabad demanded that Afghans crossing to the Pakistani side have a passport and a Pakistani visa, something that had not previously been required.