BEIRUT: Thirty-six human rights organisations joined forces on Tuesday to demand Syria's government release a prominent lawyer they say has been jailed in the war-hit country since October 2012.
"Over one and a half years after the disappearance of renowned Syrian human rights lawyer Khalil Maatuq, the undersigned organisations are reiterating their call on the Syrian authorities to release him immediately and unconditionally," said a statement signed by groups including Amnesty International.
Maatuq, director of the Syrian Centre for Legal Studies and Research, was detained along with his colleague Mohammed Thatha, as they were on their way to work in the capital Damascus, they said.
"It is believed they were detained at a government security checkpoint," said the statement.
Maatuq and Thatha's "fate and whereabouts remain unknown," it added.
"Despite repeated requests from family and lawyers, the Syrian authorities continue to deny they are in custody, placing them at particular risk of torture or other ill-treatment and extrajudicial execution."
The organisations describe the continued detention of the two men as cases of enforced disappearance.
"Enforced disappearances are crimes under international law and their use in Syria has been strongly condemned by the UN Security Council," they said.
Tens of thousands of people are believed to have been detained in Syria since an uprising broke out against President Bashar al-Assad in March 2011.
Many are thought to be held without legal charges being filed against them.