Major-General Athar Abbas, the Pakistan military spokesman, confirmed that Muhammad Aqeel, an ethnic Punjabi also known as Dr Usman, had led the attack on the army headquarters in Rawalpindi.
Aqeel, a former member of the army medical corps, is also believed to have orchestrated an ambush on Sri Lanka's visiting cricket team in Lahore in March.
According to Zulfikar Hameed, a police investigator, he is also thought to have masterminded a failed attempt to shoot down then-president Pervez Musharraf's jet with an anti-aircraft gun, and a suicide attack that killed the army surgeon-general in February 2008.
Hameed says that Aqeel was recruited into Jaish-e-Mohammed and Lashkar-e-Jhangvi, armed groups based in Punjab province.
Jaish and Lashkar have long been blamed for attacks on Western targets in Pakistan, as well as on minority Shia populations.
Both groups are believed to have had links with Pakistan security agencies, which used their members to fight proxy wars in Afghanistan and India before 2001.
The Punjab connection is significant because ethnic Punjabis dominate the army and the major institutions of the Pakistani state, Shuja Nawaz, head of the South Asia Centre at the Atlantic Council in Washington, has been quoted as saying.
"Their involvement means that their break with the military and the [intelligence services] is now complete. The question is: Will the military have the capacity to take operations against them?" he told The Washington Post newspaper.
Four attacks across Pakistan in less than a week have claimed more than 120 lives and include a 22-hour raid on the army's general headquarters in Rawalpindi, just 16km from the capital, Islamabad.
According to representatives of the Taliban, the attacks show it is not only ethnic Pashtuns who are opposed to Islamabad's government, the army and police force.
An suicide attack on Monday in Shangla, a Pashto-speaking area of the Swat valley region, killed 45 people, including six security officers, and wounded dozens of others.
The bombing was the deadliest attack in the region since the army claimed to have cleared the valley of the Taliban in an offensive earlier this year.
||October 12 - Suicide bomber targets security convoy in Shangla, near Swat valley, killing 45, including 35 civilians and six soldiers
||October 10 - Fighters attack army GHQ in Rawalpindi. Commandos storm building and rescue 39 hostages. Nine suspected Taliban fighters, 11 soldiers and three hostages killed
||October 9 - Suspected suicide car bomber kills 53 in Peshawar. About 100 people are wounded
||October 5 - Suicide bomber dressed as paramilitary soldier attacks UN office in Islamabad, killing five staff members
While many anti-government fighters were killed or captured in the army offensive, others are believed to have gone to rural areas or neighbouring districts.
Television footage of the bombing showed vegetable stands with their wares spilled on the street, two-storey buildings with their fronts torn away and several wrecked cars.
The attacker apparently targeted a military vehicle.
The Taliban has stepped up attacks in the past week as the military has been preparing to launch another major offensive on the border region of South Waziristan.
The military's aerial bombardment along the Afghan border on Tuesday is seen as a precursor to an expected ground offensive there.