The Israeli government has been accused of abandoning its fight to bring back kidnapped soldier Gilad Shalit following the decision to ease the land blockade of Gaza.
The then teenager was captured during a border raid by Hamas militants in the Gaza Strip in June 2006, and four years later the campaign to bring him home is still strong.
But speaking in the Knesset, Gilad's father Noam said the government needed to do more to ensure his return.
Mr Shalit said: "We are asking where Gilad stands in this equation. We are asking where is Gilad, our son?".
He and his wife Aviva are set to mark the anniversary of Gilad’s capture with a march across Israel, and have also said they may camp outside Prime Minister Benjamin Netanyahu’s home until their son, now 23, is rescued.
Chen Arad, whose brother Ron Arad has been missing since he was shot down in Lebanon in 1986, will be marching alongside the Shalit family. He said his brother’s story was “an example and a metaphor for what might happen to Gilad”.
He added: “Ron is a legendary character and the state has not paid its dues in his case. Something has gone wrong in the unwritten agreement between the state and its soldiers".
A number of influential voices have also added their support to the campaign, including Israeli supermodel Bar Rafaeli and California governor Arnold Schwarzenegger. A protest concert has been organised near the Gaza border by the Israeli Philharmonic Orchestra and at a rally in Paris thousands of people have gathered to call for the soldier’s freedom.
The blockade of Gaza, which has been relaxed to allow most civilian supplies in, was put in place in the aftermath of Gilad’s capture and the death of two other Israeli soldiers in the same attack.
Hamas have released brief video footage proving he is still alive, but his whereabouts are uncertain and negotiations for prisoner exchanges have so far failed.
Mr Netanyahu said the decision to lift restrictions in Gaza would strengthen demands for the international community to double or triple efforts to secure Gilad’s release.
The prime minister said: "My responsibility is both to return Gilad to his family and his nation, and also to take care of the safety and security of the people of Israel."
Gilad’s 85-year-old grandfather, Zvi Shalit, called on Mr Netanyahu to live up to this promise following a meeting with the prime minister. Mr Shalit said he stressed the urgency of the situation.
He said: “I would like to see my grandson Gilad while I am still alive.”