The Syrian regime has informed the family of a US humanitarian aid worker arrested in Damascus in 2016 that she had died in a Syrian prison almost two years ago.
The Syrian Human Rights Committee announced on Tuesday the death of Layla Shweikani, a US-Syrian dual citizen who had travelled to the Syrian capital in 2015 to help people displaced by the devastating civil war.
The London-based rights group said in an online statement that the Syrian civil registry told Shweikani's family on Monday that she had died on 28 December 2016.
It added that news of Shweikani was "suddenly cut off" on 26 December 2016 while she was detained in Damascus' notorious Adra prison.
The activist-run Syrian Revolution Network reported that Shweikani was tortured to death in the prison.
According to pro-opposition news websites, the Chicago native was detained by regime forces in February 2016 for her humanitarian work with refugees in the former rebel stronghold of Eastern Ghouta.
They have reported that she was charged with "supporting terrorism".
Tens of thousands of people are estimated to be held in regime jails across Syria, with relatives and advocates saying they are often tortured, denied fair trial, and deprived contact with families.
The Syrian Observatory for Human Rights says at least 60,000 people have died from torture or harsh conditions in regime custody since the conflict began.
The Syrian regime has been accused of various crimes during the conflict that started in 2011, including summary executions and the use of chemical weapons.
Damascus denies the allegations and has pointed to gross abuses by rebels.
Syria's war has killed nearly half a million people and displaced millions more since it erupted in 2011 with the brutal repression of anti-Assad protests.