Blinken says Syria's Assad has power to free detained journalist Austin Tice
In a statement marking Tice's 40th birthday, US Secretary of State Antony Blinken said he was personally committed to bringing him home and all other Americans detained abroad.
"He turns 40 years old today, having spent almost a quarter of his life in captivity," Blinken said.
"We believe that it is within Bashar al-Assad’s power to free Austin. We will continue to pursue all avenues to bring Austin home.
"Austin Tice must be allowed to return home to his loved ones who miss him dearly and to the country that awaits him eagerly."
Tice was a freelance photojournalist working for AFP, McClatchy News, The Washington Post, CBS and other news organisations when he disappeared on 14 August 2012 after being detained at a checkpoint near Damascus.
A State Department official told Middle East Eye in April that the US is operating "under the sincere belief that Austin Tice is alive".
The case is currently being led by Roger Carstens, the special presidential envoy for hostage affairs.
According to a report by the Associated Press, Carstens travelled to Syria last summer for a meeting between the Syrian government and the then-Trump administration. Washington planned to negotiate the return of multiple US citizens, including Tice.
The trip was unsuccessful after Syrian officials issued a list of demands, including lifting sanctions and withdrawing troops, while sharing no information on Tice's whereabouts.
There are roughly half a dozen US citizens believed to be held by the Syrian government or forces allied with Damascus, including Syrian-American psychotherapist Majd Kamalmaz.
Kamalmaz travelled to Syria from Lebanon in 2017, and according to his family, he was stopped at a government checkpoint in Damascus less than 24 hours after arriving there. That was the last time his family heard from him.
A State Department spokesperson told MEE on Wednesday that Washington calls on Syria to "help release Austin Tice, Majd Kamalmaz and every US citizen held hostage in Syria".
However, Kamalmaz's family said in June that they have been disappointed with the Biden administration's approach thus far.
Syria erupted into civil war almost a decade ago after Assad began a brutal crackdown in 2011 on protesters calling for an end to his family's rule.
At least 139 journalists have been killed while covering the conflict, according to the Committee to Protect Journalists, a New York-based watchdog.