At least 80 people were killed and over 300 wounded when a truck loaded with explosives went off in downtown Kabul near the German Embassy on Wednesday morning. All Indian Embassy staff are safe, authorities said. The Islamic State claimed responsibility for the explosion in the Afghan capital, Xinhua news agency reported.

"Ministry of Health confirms 80 dead and 319 wounded in deadly bombing in Kabul Wednesday," Tolo News Agency tweeted.

Tolo said a "truck bomb was detonated close to the German Embassy in Wazir Akbar Khan area, killing and wounding dozens".

Earlier, Tolo had quoted the interior ministry as saying that a "water tanker had been laden with explosives that were detonated on Wednesday".

According to NATO, a massive explosion occurred near the German Embassy at 8:22 am near the NATO Resolute Support headquarter in Kabul.

Foreign troops have arrived at the scene.

Images circulating on social media showed a large plume of black smoke over the city.

The blast occurred during rush hour traffic. It ripped through the diplomatic zone.

There was substantial damage to buildings in the explosion near Zanbaq Square in downtown Kabul.

It said the victims are mostly civilians and a large number of them are from the Roshan mobile company.

All staff in the Indian Embassy are safe but some windows in the building were damaged.

"By God's grace, Indian Embassy staff are safe in the massive #Kabul blast," External Affairs Minister Sushma Swaraj tweeted.