The parents of American journalist Austin Tice, who was abducted in Syria more than six years ago, said on Tuesday they were encouraged by US efforts and new details about their son's fate.
Tice was 31 when he disappeared in August 2012 near Damascus and his whereabouts remain a mystery.
But the US special envoy for hostage affairs, Robert O'Brien, said in November there was every reason to believe the journalist was alive and still detained in Syria.
His father, Marc Tice, who together with his wife Debra has relentlessly campaigned for his release, said on Tuesday that President Donald Trump's recent success in securing the release of Americans detained abroad was a source of hope.
"We're very encouraged under this new administration," he told reporters in the Lebanese capital Beirut, adding that it had "shown and developed a track record of bringing back Americans held overseas home".
He cited the three Americans who were released by North Korea in May and the US pastor Turkey freed in October.
"We're incredibly encouraged," Marc Tice said.
Neither the Syrian government nor any other entity has confirmed holding Austin Tice, but his father said: "We do believe however that the Syria government is best placed to help us get Austin safely home."
The journalist's parents said they had not received any proof of life since a 2012 video but Marc Tice stressed that there was a "consensus among all those working on his case" that his son was alive.
The couple said people whom they could not name had come forward with information on their son.
"We have recently been contacted directly by credible individuals who have shared information about Austin," Debra Tice said, without elaborating.
Austin Tice's parents said that they had made some useful contacts among the millions of Syrians who fled their country since the conflict erupted in 2011.
"Time is an ally," Marc Tice said, adding they were hoping for leads from "people that feel that their situation is secure and that they are free and less at risk in sharing that kind of information".
They also said that the million-dollar reward offered by the FBI for information leading to Austin Tice's safe return - which a coalition of media and other organisations recently announced they would match - was also a positive factor.