A new report has revealed that the US military had gathered intelligence on an Afghan hospital in Kunduz days before destroying it.

American special operations analysts had monitored the Afghan hospital well ahead of a US military attack that leveled it on October 3, the Associated Press reported on Thursday.

According to the report, US forces pressed ahead with the deadly attack because they believed the hospital was being used by a Pakistani operative to coordinate Taliban activity.

However, so far no evidence has surfaced that suggests a Pakistani was killed in the attack. Doctors without Borders (MSF), the international medical charity that ran the hospital, have also confirmed this. The MSF also said that none of its staff was Pakistani.

The special ops analysts had put together a dossier that included maps with the hospital circled on them, along with indications that intelligence agencies, using overhead surveillance, had the location and activities around it under control, according to a former intelligence official who is familiar with some of the documents describing the site.

The intelligence also suggested the hospital was being used as a Taliban command and control center and may have housed heavy weapons.

The former official, who was not authorized to comment publicly, said that after the attack, which happened during a purported battle to retake the northern Afghan city of Kunduz from the Taliban, some US analysts assessed that the strike had been justified. They concluded that the Pakistani, believed to have been working for his country's Inter-Service Intelligence directorate, had been killed.

Doctors without Borders says the US the AC-130 gunship airplane made five separate strafing runs over an hour, unleashing heavy fire on the main hospital building, which contained the emergency room and intensive care unit. Surrounding buildings were not struck, they said.

The MSF has condemned the attack as a war crime. According to the organization, the strike killed 14 hospital staff and 10 patients, and that death toll may rise.

The Pentagon initially announced that the attack was to protect US troops engaged in a firefight with militants, but President Barack Obama has since acknowledged that it was a mistake.