A blast in the Afghan capital Kabul on Tuesday caused numerous casualties, Reuters witnesses and Afghan officials said.

Kanal24 reports that a Reuters television team saw at least eight people who appeared to have been killed, besides several wounded at the explosion site in the city's Wazir Akbar Khan area.

It was the first attack targeting the Afghan capital's so-called "Green Zone" since a massive truck bomb ripped through the area on May 31, killing or wounding hundreds.

"Our initial information shows the suicide attacker was on a motorcycle. He made it through the first checkpoint but was stopped at the second checkpoint and detonated," defense ministry spokesman Dawlat Waziri told AFP.

"We don't know the target but it happened a few meters from the defense ministry's foreign relations office. No casualties to our personnel."

A public health official said three dead bodies and 10 wounded had been taken to city hospitals.