Two bomb blasts have killed at least 73 people, mostly paramilitary personnel, and wounded 100 others in the northwestern Pakistani town of Charsadda, police say.

The blasts took place outside the Frontier Constabulary's Shabqadar fort early on Friday morning, as fresh recruits were exiting the compound to board buses and coaches.

The second blast took place about eight minutes after the first, hitting the people who had rushed to the aid of those wounded by the first explosion. Police said the first explosion was caused by a suicide bomber, but that the second may have been the result of a planted explosive device.

Al Jazeera's Emma Hayward reports.