KABUL: It was like the end of the world, Anayatullah Nazari said. "It was like they were determined to kill us all and that nobody would survive. It was like doomsday, nothing I could ever imagine."

More than six weeks after a United States (US) Air Force AC-130 gunship repeatedly struck a well-marked Doctors Without Borders hospital, killing 30 people in the northern Afghan city of Kunduz, official US, Nato and Afghan government reviews have yet to be released.

But a dozen survivors interviewed by The Associated Press are convinced that the assault on the hospital – which treated wounded Taliban and government fighters alike – was no accident.

They say it was sustained and focused on destroying the main hospital building, which the aid agency says "correlates exactly" with GPS coordinates it had given to all parties in the conflict.

A Nato general blamed human and technical errors for the attack. The Pentagon insists that the Americans involved in ordering the strike didn't realise it was a hospital.

If they did, it would be a war crime.

It was just after 2 am on Oct 3 when the AC-130 shattered the first quiet evening in almost a week in Kunduz, where US and Afghan forces were locked in a ground battle to retake the city of 300,000 from the Taliban.

Suddenly, heavy weapons fire rained onto the hospital. The plane flew overhead again and again, strafing people who tried to escape until 3:15 am.

There were 105 patients, 140 Afghan staffers and nine international staff inside, along with dozens of people caring for friends and relatives, as is the Afghan custom.

When it was finally over, some had been decapitated. Some bled to death after having limbs shot off. Some were burned beyond recognition. Two patients died on operating tables.

Others died because medicine and blood supplies were destroyed. Those too ill to move were incinerated in their beds.

"One of my colleagues was trying to run away from the plane that kept coming back over the hospital," said a nurse who had gone outside to get some fresh air when the attack began.

"He ran from building to building but the plane was following him. Two other colleagues, Khalid and Tahseel, were also followed by the plane. Tahseel was hit by the guns fired from the plane and died. Khalid was injured," the nurse said, speaking on condition of anonymity for his own security.

Acting Afghan Defense Minister Masoom Stanekzai insists that the Taliban and Pakistan's spy agency directed their takeover of the city from the hospital.

National security adviser Hanif Atmar told a European diplomat that the Afghans "will take full responsibility," and that "there was no doubt whatsoever that the Taliban were inside the hospital, that they took it over, thus violating its sanctity," according to notes from the meeting reviewed by the AP.

Doctors Without Borders – also known by its French acronym MSF – rejects these assertions, and no evidence has emerged to support them.

Survivors interviewed by the AP said the compound was peaceful before the attack, and that MSF's no-guns policy was honoured.

President Barack Obama has apologised to the MSF, without explaining why the US military's chain of command approved the attack.

The AP has previously reported that US special forces had described the hospital as being under enemy control.

A senior officer in the Green Beret unit sent a report the day before, saying one of their objectives would be to "clear the trauma center" of enemy forces, and that its coordinates had been shared with "all friendly forces," according to two people who described the officer's log to the AP.

According to one account, when about 35 Army Green Berets later came under heavy fire about a half-mile from the hospital, they called for air strikes to take out Taliban "command and control centers" around the city, relaying targets provided by their Afghan allies, a former intelligence official said.

The special forces were in separate teams by then, and members involved in calling in the air strike have told investigators they were not aware the coordinates were for a hospital compound, according to an American official familiar with their account.

These sources and the former intelligence officer spoke on condition of anonymity for lack of authorization to be quoted by name.

Neither Afghan nor US ground forces had eyes on the target, American and Afghan officials said, although the gunship crew, flying in low and slow, would have seen it clearly lit up by generator-powered floodlights in the darkened city.

This sequence of events raises unresolved questions, including how the US chain of command could miss that they were firing at a hospital.

Some US officials point to a military intelligence computer network that soldiers say was not working properly in Afghanistan at the time, raising the possibility that even though many special operations analysts knew of the hospital, the information was not made available to the commanders who approved the strike.

The doctors and nurses were exhausted that night, having treated 376 patients in the emergency room in the six days since the Taliban stormed the city of 300,000.

Most were civilians, but three or four wounded government combatants and about 20 wounded Taliban also were being cared for, according to MSF's internal review, released Nov 5.

"Everyone felt like we were in the safest place in Kunduz," said Nazari, who had been at the hospital for four days caring for his brother Obaidullah, who had been wounded by crossfire. He hadn't slept for three nights, so joined other caregivers trying to rest in a safe room.

"I must have slept around five minutes before I was woken up by the smoke and the dust coming into the basement. We were sure no one could survive what was happening above us," he said.

The nurse who asked not to be identified had just left the main building when he heard the first huge explosion and saw the intensive care unit ablaze. Then he went outside and was hit by a bullet.

"After about 20 minutes of the attack going on, the plane began dropping something that was bright and burning onto the hospital. I don't know what it was, but when it hit the ground it immediately burned and flared, but with no sound," the nurse said.

MSF says the intensive care unit, emergency room, operating theatres and outpatient department, as well as X-ray, laboratory, physiotherapy, mental health and sterilization areas “all were destroyed in this wave after wave of strikes.”

MSF staff frantically called and texted US military contacts in Washington, NATO's mission in Kabul and the UN's civilian-military liaison office for humanitarian affairs in Kabul to call it off, but the Americans kept firing for more than an hour, survivors said.

A hospital security guard who also asked not to be named, for the sake of his own security, said he entered the still-smouldering remains of the intensive care unit and found that "only one person was alive - injured but alive."

"The rest were all dead. Doctors and patients were just burned. And while we were taking stock of the injured, four doctors died in the meeting room. A couple of the foreign doctors jumped out of the windows to escape the attack - it's a miracle they survived," the guard said.

Anayatullah Hamdard, an agriculture professor at Kunduz University, recovered the body of his father, Dr. Abdul Sattar. "He was completely burned. I couldn't even see his face," Hamdard said.

Also read: US military air strike hits MSF hospital in Kunduz