The allegation of mass killings came as President Donald Trump weighs options in Syria, where the US launched cruise missiles on a government air base last month after accusing Assad's military of killing scores of civilians with a sarin- like nerve agent.
Trump yesterday kicked off a week of meetings with Middle East leaders, sitting down with the crown prince of Abu Dhabi a day before he hosts Turkey's president.
All are governments that have pressed the United States over six years of civil war in Syria to intervene more forcefully. Trump had backed away from President Barack Obama's calls for regime change in the Arab country, with the new president's officials pointedly saying leadership questions should be left to Syria's citizens, until his intervention last month. His administration now says Assad cannot bring long-term stability to Syria.
In its latest accusations of Syrian abuses, the State Department said it believed about 50 detainees each day are being hanged at Saydnaya military prison, about 45 minutes north of Damascus. Many of the bodies are then burned in the crematorium "to cover up the extent of mass murders taking place," said Stuart Jones, the top US diplomat for the Middle East, accusing Assad's government of sinking "to a new level of depravity."
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The revelations echoed a February report by Amnesty International that said Syria's military police hanged as many as 13,000 people in four years before carting out bodies by the truckload for burial in mass graves.
Although the State Department cast its unusual news conference as an effort to press Assad's key backers, Russia and Iran, it also underscored Trump's lack of a strategy for stopping Syria's violence. The war has killed as many as 400,000 people since 2011, contributed to Europe's worst refugee crisis since World War II and enabled the Islamic State group to emerge as a global terrorism threat.
White House spokesman Sean Spicer yesterday reiterated the administration's line that Syria's future "should be decided by Syrians in a free credibly and transparent process." But he called such a future "unimaginable" if Assad is propped up with help from the "seemingly unconditional support from Russia and Iran." He didn't outline how such a future might become imaginable.
State Department spokeswoman Heather Nauert said Secretary of State Rex Tillerson had been "firm and clear" in a meeting with Russian Foreign Minister Sergey Lavrov last week that "Russia holds tremendous influence over Bashar al- Assad."
A main point of that meeting "was telling Russia to use its power to rein in the regime," she said. "Simply put, the killing, the devastation has gone on for far too long in Syria."
The Syrian Observatory for Human Rights corroborated the U.S. Accounts of mass killings but said it lacked sufficient information about the crematorium.