At least two people were killed and 12 injured in a blast near Afghanistan's ministry of foreign affairs on Monday, according to a hospital run by an Italian NGO in Kabul.

'We received some patients,' said Stefano Sozza of Italian NGO Emergency, which runs the surgical centre specialising in treating victims of war in downtown Kabul.

A tweet from the NGO said at least one child was among the injured.

Sozza said the incident took place near the foreign ministry.

Reuters quoted two witnesses as saying that the sound of a large explosion was heard near the heavily fortified area that is home to several government buildings and foreign embassies.

Spokespeople for the police, the information ministry and the ministry of foreign affairs did not immediately respond to requests for comment.

The cause of the blast was not immediately clear.

Kabul and other urban areas have been hit by several attacks in recent months, some of which have been claimed by Islamic State militants.

A blast in January killed at least five people and injured dozens at the Ministry of Foreign Affairs as employees streamed out of the building at the end of the working day.

Monday's incident took place around lunchtime when the city is especially crowded as government office staff leave early for the day during the holy month of Ramadan.