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.
Twelve people are killed and 70 wounded in a car bomb blast and attacks by Islamic State militants in the Syrian Kurdish town of Kobani, hospital officials in the town tell Reuters by telephone.
A global survey of 40 countries finds that large numbers of people have a favourable opinion of the United States, its economy and the US-led fight against the Islamic State.
US says an air strike in Iraq has killed an Islamic State (IS) militant linked to an attack on a US diplomatic compound in Libya 3 years ago.
Tweets and YouTube videos by fighters from the Islamic State group have allowed analysts to pinpoint their movements in Iraq and Syria, highlighting the group's increasing push towards government strongholds.
Syrian Kurdish fighters say they have taken control of the Islamic State-held town of Tal Abyad, cutting off a major supply route for the jihadist group.
Teenage girls abducted by Islamic State fighters in Iraq and Syria are being sold in slave markets "for as little as a pack of cigarettes," the UN envoy on sexual violence said Monday.
An Islamist coalition that includes Syria's al-Qaeda affiliate al-Nusra Front takes over one of the last government strongholds in western Idlib province, activists say.
Australia plans to pass a law within weeks to give the government power to strip citizenship from dual nationals who are suspected terrorists even if they are not convicted of a crime, the prime minister says.
A rare bird may become extinct in Syria because of the capture of Palmyra by Islamic State, experts say.
Saudi Arabia advertises for eight new executioners, recruiting extra staff to carry out an increasing number of death sentences, usually done by public beheading.
