At least 40 people were killed or wounded as a massive explosion was reported near Indian Embassy in Kabul on Wednesday morning, sending clouds of black smoke spiralling over the centre of the city in an area near the presidential palace and foreign embassies, according to media reports.

"More than 60 wounded people, mainly civilians, had been rushed to Kabul hospitals," Afghanistan Interior Ministry spokesman Najib Danish was quoted as saying by a news agency.

"We don't know the number of deaths yet," he added.

Ministry of External Affairs sources said that all staff at the Indian embassy were safe.

But some damage to the windows of the embassy building has been reported.

It was not immediately clear what was the target of the blast, the latest attack to hit the Afghan capital.

The blast took place 50 metres away from the Indian Embassy.

According to reports, all houses near the blast site were damaged with windows and doors blown off their hinges.

(With inputs from agencies)