In the first incident, four police officers and a child were killed when a remote-controlled bomb exploded near a police vehicle in the Lahori Gate area.

Later, a woman suicide bomber killed herself and another woman, possibly her companion, by detonating her jacket.

She was trying to target the police checkpoint about 400m from the spot where the police vehicle was hit.

Militant attacks in Pakistan have risen sharply since May, when US commandos killed al-Qaeda leader Osama Bin Laden.

Since then, a paramilitary academy, a naval base, government buildings, a police station and a US consulate convoy have been attacked.

In the first attack on Thursday morning, the explosive device was hidden in a handcart parked at the roadside and detonated remotely when police approached, police officer Ijaz Khan told reporters.

A 12-year-old boy was among those killed. At least 21 people, including 17 policemen, were injured in the blast.

In the second attack, police said the bomber appeared to be a woman about 16 or 17 years old. Her clothes suggested she could have been from the tribal region.