Taliban security forces block a road after a suicide blast near foreign ministry at the Zanbaq Square in Kabul on Wednesday. AFP

Ustad Fareedun, an official at the Taliban-run information ministry, said the bomber had planned to enter the foreign ministry but failed. "Twenty people were killed and many other injured in the suicide attack," he said.

A photo of the area, confirmed by official sources, showed at least nine people wounded or killed, lying outside the ministry as security forces attended to them.

The blast hit at about 4pm local time, Kabul's police spokesperson Khalid Zadran said. He did not provide details on the number of casualties, saying officials were investigating.

The Taliban-run administration has faced an insurgency by Daesh militants who have targeted foreigners at certain sites, including the Russian and Pakistani embassies and a hotel catering to Chinese businessmen.

The blast took place at a busy time of day in a heavily fortified area surrounded by checkpoints on a street housing several ministries.

A person in a nearby office, who asked not to be named, described hearing a loud explosion and said they were evacuated from their building.

Some countries, including Turkey and China, also have embassies in the area.

Reuters