In the southwest of Kabul insurgents managed to climb a five-story building site from where they fired on the Afghan parliament, the commerce ministry and the Russian embassy. Some members of parliament, which is full of battle-hardened former mujahideen commanders who fought a guerrilla campaign against Soviet occupying forces in the 1980s, grabbed weapons and joined parliamentary guards to try to repel the attack.
Pamir Patang, chief of staff at the neighboring commerce ministry, said that the military attache at the nearby Russian embassy had reported that Russian soldiers inside the compound returned fire on the multistory building site from which they were being attacked, in what could be the first time Russians have been engaged in combat in Afghanistan since 1989.
A high profile Afghan member of Parliament, Wazhma Frogh, who was caught up in the attacks near the British embassy gave a scathing verdict on the response of police: "I was nearly shot in the back as I was walking down the street, not by a terrorist but by the Afghan police who were just shooting at everything," she said. "They had no idea where they were firing."
The attacks, Frogh said, cast doubt on NATO's transition plan, which aims to hand over full responsibility for security to the Afghan government by the end of 2014.
"This shows just how ridiculous the transition policy is. I've never seen a street battle before, but what I saw today was the fragility of these police officers. It really shows how poor police training has been.
"At the same time the insurgency has been so smart," she added. "They have become so sophisticated and well trained. They can attack major buildings if they want and our intelligence agencies have no idea."
Gen. John Allen, commander of the International Security Assistance Force, said he was "enormously proud" of the response mounted by Afghan security forces. He added: "No one is underestimating the seriousness of the attacks, and we'll work hard to determine the circumstances that led to today's events."
In the past such elaborate attacks on the Afghan capital have been blamed on the Haqqani network, a group allied to the Taliban with a proven ability to mount complex, headline grabbing operations.
Even as the attacks continued, Afghan analysts pointed the finger of blame at Pakistan's military spy agency, Inter-Services Intelligence (ISI), which has been linked to previous Haqqani attacks.
Patang said it was too early to say with any certainty whether the ISI was to blame. "However, what we can say for sure is that so many simultaneous attacks in different places around the country can only be sponsored violence. This is an insurgency that can only be supported by a professional intelligence agency."
Pakistan's foreign minister Hina Rabbani Khar expressed her country's "deep concern" at reports of the attacks in Afghanistan. "Pakistan strongly condemns terrorism in all forms and has consistently encouraged dialogue to resolve issues in Afghanistan," she said.
Directly to the south of Kabul, in Logar province, a group of suicide bombers managed to enter the offices of the provincial governor and the police chief.
In the east, two suicide bombers blew themselves up outside Jalalabad's airport, wounding several people.
And in Gardez, in the eastern province of Paktia, several gunmen attacked a police training center.
As the Afghan capital erupted in gunfire, the streets of the central shopping district, Shar-e-Naw, emptied as shop owners closed down and went home.
However, many Kabul residents have become remarkably desensitized to outbreaks of violence.
"All the internationals got up and left, but the Afghans just stayed to finish their meals," said businessman Khaleeq Ahmad who was having lunch on the top floor restaurant of one Kabul's most exclusive hotels when gunfire broke out all around the city. "Afghans are pretty resilient. They have seen so many things they just don't care," he said.
Nonetheless, he said many Kabul residents will be shocked by the scale of violence after a lull in Taliban activity of seven months, which by Kabul standards is a long time.
"Of course it will scare people for a while," he said. "But everyone has kind of got used to it. It doesn't stop their daily lives."
Intellpuke: You can read this article by Guardian correspondents Jon Boone and Emma Graham Harrison, reporting from Kabul, Afghanistan, in context here: www.guardian.co.uk/world/2012/apr/15/taliban-largest-attack-kabul