No group has claimed the four activists' abduction and they have not been heard from since.
Ankara-backed rebels played a key role in supporting Sharaa's Islamist group Hayat Tahrir al-Sham (HTS), which headed a rebel alliance that seized Damascus on December 8, toppling longtime ruler Bashar al-Assad.
The seismic change in Syria is expected to yield deeper Turkish sway just as a change of US administration is raising questions over how long Washington will keep backing the country's Kurdish-led forces.
Assad fled Syria following a lightning offensive spearheaded by the Islamist Hayat Tahrir al-Sham (HTS), more than 13 years after his crackdown on democracy protests precipitated one of the deadliest wars of the century.
Darwish was detained for months by one of the most feared branches of the former government's many-tentacled intelligence services.
Syrians will not miss Assad, a brutal ruler who failed his people.
The offensive, which took just 10 days to sweep across Syria and take the capital Damascus, stunned the world and brought an end to more than a half a century of brutal rule by the Assad clan.
"We would like to see the situation in the country stabilised somehow as soon as possible," Kremlin spokesman Dmitry Peskov told reporters.
"Their human capital, their experience will allow the country to flourish," Bashir said in an interview published Wednesday.
The White House has strongly condemned a visit to Moscow by Syrian President Bashar al-Assad.
Syria's President Bashar al-Assad has visited Moscow on his first overseas trip since the civil war broke out in his country in 2011.
At least 45 people have been killed in Russian air strikes on a rebel-held area of north-western Syria, a monitoring group says.
The crush and stampede that struck the hajj last month in Saudi Arabia killed at least 2,177 pilgrims, a new Associated Press tally showed on Monday.
Slovenia says it has allowed most of the 5,000 people who were stranded in wet and muddy conditions on its border with Croatia in the country.
40 militants with the so-called Islamic State are killed in air strikes in Syria, a British-based monitoring group reports.
Eighty-four Church of England bishops reveal that they wrote to David Cameron last month urging him to accept at least 50,000 refugees from Syria.
EU states have approved an action plan for Turkey that it is hoped will ease the flow of migrants to Europe.
European leaders are to discuss measures to ease the region's migration crisis, with Turkey the focus of their efforts in Brussels.
The fortunes of President Bashar al-Assad, and the possibility of peace in the region, have suffered many setbacks, and they face so ...
