In a dilapidated Y-shaped military prison near Damascus, the Syrian government quietly and brutally executed its own people, according to an alarming report released by Amnesty International.

The 48-page report claims Syria secretly carried out mass hangings at the Saydnaya Military Prison to eliminate those who spoke out against the government. At least 13,000 people were hanged the past five years, most of them in batches of 50, the report said.

“The most important finding here is that the government has been launching a calculated campaign of exterminations in this prison,” Nicolette Waldman, a Middle East and North Africa researcher at Amnesty International who authored the report, told Fox News. “This is not an isolated incident, but a planned and strategic campaign to root out opposition in the civilian population and even kill those against Syrian authorities.”

The report is just the latest look at the humanitarian crisis that persists in Bashar al-Assad’s Syria. Amnesty International’s investigation, spanning from December 2015 to December 2016, consisted of interviews with former Saydnaya prison officials, guards, and former detainees who gave testimony and were “witnesses to the sounds and sights” of certain executions. The bodies, according to witnesses, were eventually dumped at mass graves on military land near the country’s capital.

One former prison guard told Amnesty International that “Saydnaya is the end of life – the end of humanity.”

There are two detention centers at Saydnaya Military Prison, which, according to the report, may hold up to 20,000 people. In the “red building”, the majority of detainees are civilians who have been arrested since the beginning of the crisis in 2011. In the “white building”, the majority of the detainees are officers and soldiers in the Syrian military who have been arrested since 2011.

The report said the detainees were never given a fair trial. Instead, they were tortured until they gave false confessions. Government leaders, the report said, knew the prison was a human slaughterhouse yet turned a blind eye to it.

“We believe these practices are known about and approved by the highest level of the Syrian government,” Waldman told Fox News. “People need to understand that Saydnaya has been manufactured to be a place of slaughter for human beings.”

The State Department told Fox News that they are in the process of reviewing the report.

“Our initial assessment is that we’re not surprised by its allegations as it would be keeping with Assad and his regime’s brutal tactics, which include systematic human rights violations,” Mark Toner, acting State Department spokesperson, told Fox News via email.

The report outlined recommendations to address the situation at the prison, calling for a United Nations investigation into crimes against humanity as well as allowing independent monitors to have “unfettered access” to Syrian prisons.

“Saydnaya’s prison is notorious and known by all opposing groups to the Assad regime,” said Walid Phares, a Fox News contributor and former foreign policy advisor to President Trump during the campaign. “Many reports have surfaced about the breaches at Saydnaya targeting Syrian opposition members and citizens.”

Phares said the United Nations and the United States should demand Syria to release all of its political prisoners.

Former Congressman Dennis Kucinich (D-Ohio), who recently returned from a humanitarian fact-finding mission in Syria, said he was disturbed by the report’s findings.

“Killing of innocent civilians is fundamentally wrong and if this report is true, it raises questions of great consequence for international law,” Kucinich told Fox News.

While the report only looked at one prison, Waldman said the group would not be surprised if similar executions were being carried out other Syrian prisons.

“It would be very concerning if this was the tip of the iceberg, which we hope is not the case, but it’s important we immediately determine what’s going on,” Waldman told Fox News. “We need to bring these atrocities to an end.”