ISLAMABAD -- At least 13 people were killed and over 20 others injured when a suicide bomber blew himself up near a police check post jointly owned by police and Pakistan army on Monday morning, officials said.

Haroon Joya, Superintendent police, said that a teenager suicide bomber riding a bicycle blew himself up in the middle of Royal Artillery Bazar, located around 500 meters away from the General Headquarters of Pakistan army in Rawalpindi, the sister city of Pakistan's capital Islamabad.

He said that six security personnel and seven civilians including a woman and two school kids were among the killed, while the injured included security personnel and school kids who were passing by the blast site.

Police said that they found leg of the suicide bomber with a black shoe from the blast site.

According to initial reports the bomber was carrying an estimated 5-8 kg of explosives which were used in the blast.

The injured have been shifted to District Hospital and Military Hospital where several of them were said to be in critical condition.

Shortly after the blast, Shahid Ullah Shahid, spokesperson of Pakistan Taliban, claimed responsibility for the blast saying that they would keep on targeting security forces in the future.

He said they are targeting and would target forces in response to the ongoing operation in the country's tribal areas, and killing of their leader Wali ur Rehman.

This is the second attack on the security forces over the last 24 hours, earlier on Sunday morning, 23 troops were killed and over 30 others injured when a suicide bomber hit an army convoy in northwest Pakistan.

Following the blast, both Prime Minister Nawaz Sharif and President Mamnoon Hussian condemned the blast and directed hospital administration to provide best possible medical facilities to the injured people.