Syrian President Bashar al-Assad is the latest figure to play the fake news card as he rejects claims he had 13,000 people executed in one of his prisons.

Amnesty International published a shocking report this week stating victims were given death sentences after sham trials lasting less than three minutes, often on the basis of confessions extracted through torture and all commissioned by top officials.

The government's leader reacted to the allegations of mass execution by calling the report false, saying people could 'forge anything these days', suggesting the charity bribed officials in order to produce a biased report.

A spokesman for the charity told MailOnline Amnesty Internationally 'robustly rejected' the claims.

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President Bashar al-Assad has hit back at reports of mass executions in one of his prisons

Up to 50 people at a time were collected from Saydnaya Prison (pictured) and taken to a cell in the basement of the red building (top right)

Smoke rises after warcrafts belonging to Assad Regime forces carried out airstrikes to a marketplace and a settlement in Arbin town of Eastern Ghouta region in Damascus, Syria

In an interview with Yahoo News' Michael Isikoff, Assad said the charity's report was a bi-product of a 'fake news era'.

During the interview, Assad turned the questions around on his American interviewer to duck talking about the prison in question, saying the US was in no position to talk about human rights because of the country's relationship with Saudi Arabia.

Isikoff pointed out he was not interviewing the King of Saudi Arabia, but was interviewing Bashar al-Assad, to which the president said: 'You own the questions. I own the answers. And that is my answer.'

Eventually, he addressed the issue, saying all Amnesty International reports are biased and politically-motivated, something a spokesman for the charity told MailOnline they robustly rejected.

'It's a shame they publish a report without a shred of evidence,' he told Yahoo News.

'What about the documents? The concrete evidence?'

Syrian President Bashar al-Assad

Iskikoff pointed out the interviews were with four prison officials and guards, three senior Syrian judges and three doctors.

But Assad hit back suggesting the charity bribed officials when compiling their report, again something Amnesty International denied.

He said: 'It means nothing. You can make any report - you can pay money to anyone [to say what you want them to say].'

The Syrian leader went on to laugh at the reports of 13,000 executions, and admits he has never been to the prison as he was in the presidential palace.

He refused to open an investigation to the case.

In response to the interview, Amnesty International’s research and advocacy director for the Middle East and North Africa Philip Luther said: 'In his interview President Bashar al-Assad repeatedly attempts to discredit Amnesty International’s findings.

'However, he admits he has not visited Saydnaya military prison and provides not a shred of information about the "true" situation there.

'He acknowledges that executions take place in Syria, but fails to give any details whatsoever about the number carried out in Saydnaya or anywhere else in the country.

'If he has nothing to hide he must immediately grant access for international monitors to Saydnaya and all other places of detention in Syria.

'He must also reveal the truth about the number of executions taking place.

'Russia, which has also publicly dismissed the findings of the report, should use its influence with the Syrian authorities to make this happen.'

Earlier this week, Boris Johnson said he was 'sickened' by reports that Bashar al-Assad's regime tortured and hanged 13,000 political prisoners in four years.

Amid compelling evidence that the Syrian president's henchmen carried out an unprecedented 'policy of extermination', the Foreign Secretary said the dictator had 'no future as leader'.

Civilians perceived to be opposed to the brutal regime – including doctors and aid workers – were executed in mass hangings of up to 50 detainees at a time, according to a chilling Amnesty International dossier.

Victims were given death sentences after sham trials lasting less than three minutes, often on the basis of confessions extracted through torture, the human rights charity said.

If he has nothing to hide he must immediately grant access for international monitors to Saydnaya and all other places of detention in Syria Amnesty International’s research and advocacy director for the Middle East and North Africa Philip Luther on President Assad

Many thousands of others held at the notorious 20,000-capacity Saydnaya military prison, north of Damascus, died from starvation and disease.

The charity's year-long investigation drew on graphic accounts from witnesses, including judges, officials and former guards at the prison.

One source, a former military officer known only as Hamid who was arrested in 2011, described hearing the killings taking place from the floor above.

He said: 'If you put your ears on the floor, you could hear the sound of a kind of gurgling. This would last around ten minutes ... We were sleeping on top of the sound of people choking to death.'

The bodies of those hanged are believed to have been dumped in mass graves on military land on the outskirts of the war-ravaged capital.

The report said it was 'inconceivable that these large-scale practices have not been authorised at the highest levels of the Syrian government'.

Many thousands of others held at the notorious 20,000-capacity Saydnaya military prison (pictured), north of Damascus, died from starvation and disease, according to Amnesty International

Boris Johnson said Bashar al-Assad had 'no future as leader' after compelling evidence showed he carried out an unprecedented 'policy of extermination

It is the first evidence said to prove that Assad, 51, has authorised torture to punish opponents and crush dissent.

He has long been suspected of such action.

Individual death sentences are supposed to be approved by either the Syrian minister of defence or the chief of staff of the army, both of whom are authorised to act on behalf of Assad.

Following publication of the study, Mr Johnson tweeted: 'Sickened by reports from Amnesty International on executions in Syria.

'Assad responsible for so many deaths and has no future as leader.'

His comments appeared to back away from his suggestion last month that Assad could be allowed to run for re-election in a bid to end Syria's civil war, which has left nearly 400,000 dead and half the population displaced.

But at a Cabinet meeting earlier this week, Mr Johnson made clear the dictator could not remain in power.

A spokesman for the Prime Minister said: 'The Foreign Secretary stressed that Britain [doesn't] believe that Assad can govern the country or take control of its democratically elected government.'

Lynn Maalouf, (pictured) deputy research director at Amnesty International in Beirut, said: 'The horrors depicted in this report reveal a hidden, monstrous campaign'

Amnesty's report, titled Human Slaughterhouse, reveals that as well as extrajudicial executions, the Syrian authorities are deliberately inflicting horrific conditions on detainees, including torture and denial of food, water and medicine.

Since the uprising began in 2011, the prison has been filled with those accused of opposing Assad or taking part in anti-government protests, as well as military personnel said to be working against the regime or plotting to defect.

Upon arriving at Saydnaya, they undergo a brutal session of beating – referred to as the 'welcome party'.

Witnesses described a methodical routine to the killings, in which the doomed detainees were collected from their cell blocks in the afternoon and told they were being transferred to civilian prisons.

Instead, they were moved to a facility in the grounds known as the 'red building', where they were beaten for several hours.

Between midnight and 3am, they were then blindfolded and moved in delivery trucks and minibuses to another part of the jail called the 'white building'.

There, they were taken into a basement room, nooses were placed around their necks and they were hanged.

Following the executions, the prisoners' bodies were taken to Tishreen military hospital where they were registered as having died of natural causes.

The corpses were then loaded on to trucks to be secretly buried in mass graves, the report said. Families of the dead were never informed.

Amnesty said the evidence, from between 2011 and 2015, amounted to crimes against humanity and called on the UN to investigate.

This is a floor plan of the 'execution room' inside the Saydnaya Prison, which is north of the capital Damascus, Syria

Lynn Maalouf, deputy research director at the charity's office in Beirut, said: 'The horrors depicted in this report reveal a hidden, monstrous campaign, authorised at the highest levels of the Syrian government, aimed at crushing any form of dissent within the Syrian population.

'The cold-blooded killing of thousands of defenceless prisoners, along with the carefully crafted and systematic programmes of psychological and physical torture that are in place inside Saydnaya prison cannot be allowed to continue.

Those responsible for these heinous crimes must be brought to justice.' The report adds to previous evidence of abuses, which could result in Assad and key figures in his regime being hauled before international courts charged with crimes against humanity.

In August 2013, a defector known only as Caesar fled Syria with files containing photographs of the bodies of more than 28,000 victims who had died under torture in prison.

The state of the bodies – which were covered in horrific wounds – and their sheer number revealed the scale of the abuse.

Amnesty's report was published ahead of talks in Geneva aiming to end the bloody civil war.

Assad's representatives are preparing to meet officials from Turkey, who have backed the rebels, later this month.

Russia and Iran, both Assad's allies, will join the talks.