The war of words between the Taliban and United States President Donald Trump escalated on Thursday as the Afghan militants warned that the US leader had failed to grasp “what type of nation he is dealing with”.

The latest salvo in the bitter exchange comes a day after Trump boasted during a 9/11 anniversary ceremony that US forces have “hit our enemy harder than they have ever been hit before and that will continue” just days after peace talks between the two sides collapsed.

“Trump (@realDonaldTrump) must tread carefully,” tweeted Taliban spokesman Zabihullah Mujahid. “He has yet to grasp the type of nation he is dealing with. His advisers must make him understand and introduce the Graveyard of Empires #Afghanistan to him.”

Explainer: How Trump upended US-Taliban peace talks

Until this weekend, there had been steadily mounting expectations of a deal that would see the US draw down troop levels in Afghanistan.

In return, the Taliban would offer security guarantees to keep extremist groups out. But then on Saturday, Trump revealed on Twitter that he had cancelled an unprecedented meeting between the Taliban and himself at Camp David and later said the talks with the militants were “dead”.

The Taliban spokesman's tweet comes just hours after the group launched a suicide attack that killed at least four soldiers near Kabul, as the insurgents ramp up attacks on security forces.

The incident occurred at a special forces base in Char Asiab district just south of the capital Kabul where an insurgent driving a car packed with explosives detonated near the facility's entrance.

“Four soldiers were killed, and three injured,” said interior ministry spokesman Nasrat Rahimi.

Afghan special forces — numbering around 17,000 — represent a small fraction of the 300,000 strong Afghan armed forces but have been carrying out the bulk of offensive operations across Afghanistan in recent years.

As fears of increased violence soared with presidential elections approaching later this month, Afghan troops and Taliban insurgents have been engaged in heavy exchanges across the country, with several militant-controlled districts in the far north falling to government forces.

However, the Taliban continue to strike Afghan installations at will after the militants issued their own vow earlier in the week to continue fighting and make the US regret walking away from talks.