A teenage suicide bomber killed up to 31 Pakistani army recruits at a parade ground on Thursday, an attack the Taliban said was revenge for US drone strikes and local military offensives.

Wearing school uniform, the young teen blew himself up at the parade inside a heavily guarded military compound just outside the town of Mardan, killing the soldiers with shrapnel and explosives, officials said.

It was the deadliest suicide bombing in Pakistan since a woman with a bomb strapped under her burqa killed 43 people at a UN food distribution point on Christmas Day in the tribal district of Bajaur.

The Taliban claimed responsibility and threatened “bigger attacks” in coming days to avenge American drone strikes and Pakistani military operations targeting militants in the northwestern tribal belt.

“It was a suicide attack. The teenager bomber was on foot and was wearing a school uniform,” Abdullah Khan, a senior police officer in Mardan, around 30 kilometres from the regional capital Peshawar, told AFP. “The death toll has now reached 31 recruits. Thirty-six have been injured, Sixteen of them are critical,” Khan told.

“The bomber was 14 or 15 years old. He was not a student at the school inside the regiment. He came from outside but was dressed like the other school boys.”

After the attack, soldiers in bulletproof jackets and helmets cordoned off the entire area around the Punjab Regiment Centre, deploying jeeps mounted with machine guns and preventing access to the site.

Pakistan suffers near-daily attacks blamed on Taliban and Al-Qaeda-linked militants the attacks have killed more than 4,000 people since government troops evicted Islamists from an Islamabad mosque in a deadly July 2007 siege.

Most of the violence is concentrated in the northwest, where Washington has branded the lawless tribal belt snaking along the border with Afghanistan the global headquarters of Al-Qaeda and the most dangerous place on Earth.