US President Donald Trump suggested in a recent address to the nation that American troops will remain in Afghanistan until the country "becomes able to defend itself".

The head of state said that a hasty withdrawal would create a vacuum of power that terrorists could use to tighten their grip on the country.

A US-led invasion of Afghanistan began in 2001 to dismantle terror group Al-Qaeda and remove the Taliban, a Sunni fundamentalist political movement, from power.

Contrary to expectations, Trump did not disclose the number of possible soldiers that could be further deployed to Afghanistan, where some 8,000 US special forces are still providing support to the Afghan army.

Washington's new strategy in Afghanistan seems to be in contrast with Trump's previous line of thought.

The leader, who took office in November 2016, had criticised past administrations for having deployed troops to the war-torn country, arguing that the strategy had failed to root out terrorism and was leading US to "slaughter".

On several occasions, the business figure and TV star – already well known in the US before becoming president – took to Twitter to voice his disapproval and call for a "speedy withdrawal".

The Taliban took control of Afghanistan in 1996, imposing a strict version of Islam and persecuting anyone who would not abide by their laws. Although Taliban rule ended in 2001, its insurgents still control some areas of the country and carry out deadly attacks.

Afghanistan is also witnessing a surge in attacks at the hands of the Isis terror group, which established a foothold in the country in 2015.