U.S. Secretary of State Antony Blinken called on Syrian President Bashar al-Assad Wednesday to free U.S. journalist Austin Tice, who was kidnapped nine years ago while reporting in Damascus on the uprising against Assad. “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,” Blinken said in a statement released on Tice’s 40th birthday. Blinken said a team that includes Special Presidential Envoy for Hostage Affairs Roger Carstens is “working diligently and around the clock to bring Austin back to his family.” The identity of Tice’s abductors remains unknown and there has been no claim of responsibility. The Syrian government has said it was unaware of Tice’s whereabouts. Video and information released about a month after Tice’s kidnapping suggested he was being held by an armed group allied with the Syrian government, according to media reports.