Media playback is unsupported on your device Media caption David Loyn reports from outside the Kabul shrine where Farkhunda was killed

An Afghan appeals court has quashed death sentences imposed on four men for their part in the mob killing of a young woman in Kabul in March.

Farkhunda Malikzada was attacked at an Islamic shrine after being falsely accused of burning a copy of the Koran.

She was stoned to death, her body was run over by a car and set on fire.

The court also acquitted the keeper of the shrine. Family members and rights activists have expressed outrage at the decision, which was taken in secret.

Wednesday's appeal court hearing in Kabul was held behind closed doors.

Judge Ali Masir Murid told the BBC that three of the condemned men had been sentenced to 20 years in jail; a fourth received 10 years because he is a minor.

One of these four men was the amulet seller Zainuddin, who had the original argument with Ms Malikzada, 27, the BBC's David Loyn in Kabul reports. The caretaker of the shrine, Omran, was acquitted, he adds.

Image copyright Reuters Image caption The brutal killing shocked the world and has been seen as a potential watershed in Afghanistan

Analysis: David Loyn, BBC News, Kabul

The way the appeal was heard, in a closed court, with no journalists or other observers present, is only one of the troubling aspects of this decision. Exact details of the ruling have not yet been formally announced, but this does appear to be the final appeal hearing.

Prominent women's rights activist Wazhma Frogh said that if the keeper of the shrine does now walk free, then she is "completely outraged".

"Farkhunda was killed because she was a woman," she said. And the judges have treated her case lightly. In Afghanistan, "not only the Taliban, but the whole system is oppressing women", she added.

The widespread anger both here and around the world about the murder led to unusual transparency, with cameras allowed into the first court appearances. But that openness has not been continued through the appeals procedure.

Ms Malikzada's brother Najibullah told BBC Persian: "It's not a court, it's just a show... The media should have been there, we should been there, the lawyers should have been there.

"It's a real theatre. The whole world laughs at the judicial system of Afghanistan. Do the judges have families, sisters, mothers - or not? Do they have a heart? We will not accept this decision."

He accused the authorities of "a tyranny" against the family, who have been living in fear since the attack.

At the original trial in May, eight men were given jail terms of 16 years, as well as the four who received death sentences.

Later in the month, 11 policemen were sentenced to one year in prison for failing to protect Ms Malikzada, a devout Islamic student. Eight other police officers were acquitted.

The treatment of the police was condemned as too lenient, in a country where women are frequently denied justice.

Kimberley Motley, an American lawyer in Afghanistan who represented the family during the previous trial, also criticised the ruling.

"I'm extremely surprised and disappointed. I'm very concerned because this happened in a very closed hearing, it wasn't transparent as the first court was and so there's questions as to why this even occurred.

"There's very strong evidence through video and through eyewitness testimony that justified the original sentences that were imposed on these men."