Foreign forces should hold 'no hope' of keeping a military presence in Afghanistan after the US and NATO withdraw troops, the Taliban said Saturday, warning the security of embassies and airports would be the responsibility of Afghans.

It comes as western diplomats and military officials scramble to work out how to provide security for any future civilian presence they keep in the country.

Turkey has reportedly said it is prepared to keep troops in Afghanistan to protect Kabul airport, the main exit route for western diplomats and humanitarian workers. 

"Every inch of Afghan soil, its airports and security of foreign embassies and diplomatic offices is the responsibility of the Afghans, consequently no one should hold out hope of keeping military or security presence in our country," a statement issued by the Taliban on Saturday said.

"If anyone does make such a mistake, the Afghan people and the Islamic Emirate shall view them as occupiers and shall take a stance against them," it added.

The United States is in the final stages of completing a military drawdown, alongside NATO forces, by September 11 -- twenty years after they invaded Afghanistan and toppled the Taliban.

The decision to end America's longest war has raised fears that an emboldened Taliban could topple the Western-backed government in Kabul. 

The possibility of keeping troops in Afghanistan is expected to be discussed during a meeting of NATO leaders in Brussels on Monday.

NATO Secretary General Jens Stoltenberg said last month the alliance would provide funding to help run Kabul airport and train Afghanistan's special forces after it had left.

Turkish media later reported that Ankara was willing to maintain a presence in the country, including at the country's main gateway, if NATO provided financial support.

The Taliban has attempted to calm foreign missions by saying they could "continue their operations as usual", after Australia closed its embassy citing an "increasingly uncertain security environment".

The militants have in recent weeks made territorial gains in and around the country, including in provinces close to the capital.

On Saturday, at least seven civilians were killed in two separate explosions in the city, the Interior Ministry said, the latest in a series of bombings targeting buses. 

There was no immediate claim of responsibility.