“Austin was taken captive three days after his 31st birthday,” Debra and Marc Tice said in a joint statement at the news conference.

“We can only imagine the things he was dreaming of doing – what he might have accomplished, enjoyed, and experienced during these five important years of his early thirties, including his graduation from law school. We are willing to engage with any government, group, or individual who can help us in our efforts to secure Austin’s safe release.”

They also referred to the video posted on YouTube six weeks after his abduction that showed him blindfolded and handcuffed between armed captors. This video continues to be the only evidence that he did not die on the day he disappeared.

“We now realize that the response to that video was not appropriate,” they said. “No one, including us, asked about a next step to engage toward Austin’s release. Realizing this horrible mistake, we now plead with those holding Austin to reach out to us again and give us another chance to communicate.”

Alexandra El Khazen, the head of RSF’s Middle East desk, said: “Austin Tice is the only US journalist still held in Syria. It is thanks to his courage and the courage of other foreign and Syrian journalists that the Syrian civil war can be regarded as one of the best covered conflicts of all times.”

Pointing out that governments are required by international law to protect journalists, El Khazen added: “Like Austin Tice’s parents, we ask the Syrian and US governments to do everything in their power to bring this journalist home.”

Skeyes Centre executive director Ayman Mhanna said: “Austin Tice’s release would be a source of hope not only for his family but also for media freedom in the region and for all the other journalists detained or missing in Syria. His return would be a step towards a positive resolution of the conflict and towards an end to the Syrian people’s tragedy.”

RSF has been assisting and advising the Tice family since September 2012. In February 2015, around 300 US news websites participated in the #FreeAustinTice campaign, which was designed to draw the public’s attention to his plight.

Syria has been the world’s deadliest country for journalists for the past several years. Acts of intimidation, arrests, kidnappings and murders are all frequent and constitute a gruesome tableau. It is ranked 177th out of 180 countries in RSF’s 2017 World Press Freedom Index.