The European Court of Human Rights (ECHR) warned Bulgaria on Thursday that expelling asylum-seeking members of China's Muslim Uighur community "would constitute a violation" of their rights.

Back in China, the Uighurs could be "at risk of arbitrary detention, ill-treatment and death," the court said in its ruling, telling Bulgaria "not to remove the applicants."

Sending them back to China, or to another country without guarantees that their rights would be protected, would violate articles 2 and 3 of the European Convention on Human Rights -- the right to life and the right not to be tortured.

The court was ruling in an application by five Muslims who fled China's Xinjiang Uighur Autonomous Region (XUAR) under accusations of "terrorism" links. They arrived in Turkey between 2013 and 2015, and made their way to Bulgaria in July 2017, albeit illegally.

Bulgaria refused their asylum applications, saying they had failed to show they had to leave China because of ethnic or religious persecution, or that they would face any if they returned. They were also considered a security threat for allegedly having undergone training for the separatist East Turkistan Islamic Movement, listed as a "terrorist" group by the United Nations.

Bulgarian authorities were preparing to expel the five people when they appealed to the ECHR. The court ruled in January 2018 that Bulgaria should not remove the applicants while the case was pending.

"The relevant information on the current situation in the XUAR showed that the Chinese authorities had proceeded with the detention of hundreds of thousands or even millions of Uighurs in 're-education camps', where instances of ill-treatment, torture and death of the detainees had been reported," the court said Thursday. "That had been the case of many Uighurs who had returned to China after leaving the country or who had been forcibly repatriated," it said.

Given the general situation and the applicants' individual circumstances, "there were substantial grounds for believing that they would be at real risk of arbitrary detention and imprisonment, as well as ill-treatment and even death, if they were removed to their country of origin," it added.

There were also no guarantees that, in sending them to a third country, Bulgaria would "properly examine whether they would in turn be sent from there to China without due consideration for the risk of ill treatment and even death."

Two of the five Uighurs have since left Bulgaria on their own accord, and the ruling does not apply to them.