A suicide bomber killed at least 12 people outside a court building in Pakistan’s capital Islamabad on Tuesday, Interior Minister Mohsin Naqvi said.

Several others were wounded and some were in a critical condition, a hospital source said.

The bomber tried to enter the court building on foot, but detonated the device outside, close to a police vehicle, after waiting there for 10 to 15 minutes, Naqvi told reporters at the site.

"We are investigating this incident from different angles. It is not just another bombing. It happened right in Islamabad," the minister said.

The blast hit near the entrance of Islamabad district court, which is typically crowded with a large number of litigants.

People covered in blood lay next to a police van, in videos and pictures on local media.