A huge explosion has shaken the Afghan capital, Kabul, sending a plume of black smoke over the city's western suburbs.

The cause was no immediately known. The deputy chief of Kabul police, Sayed Gulagha has confirmed it was an explosion and says it appears to have occurred near a busy shopping district.

The explosion comes as government employees are leaving their offices at the end of the working day, which is shorter during the Ramadan month of fasting.

It comes a week after an audacious attack on the nation's parliament, which highlighted the ability of insurgents, who have been fighting to overthrow the Kabul government for almost 14 years, to enter the highly fortified capital to stage deadly attacks.