The parents of Gilad Shalit, an Israeli soldier held in the Gaza Strip since 2006, have begun a 12-day march from their home to the Israeli prime minister's residence to press for a prisoner swap.
Aviva and Noam Shalit, the soldier's parents, left their home in Israel's north on Sunday and were joined by hundreds of supporters.
"Today we go out on a long and tiring journey and we will return home only with Gilad. With the help of the public who joined us during the entire way and with your help we will go back home with Gilad," Aviva Shalit, Gilad's mother, said.
Hundreds of Israelis held signs and waved Israeli flags calling for the release of the soldier.
Noam Shalit, Gilad's father, addressed the crowd and said that the Israeli government has only provided excuses for the delay of his son's release.
"We waited for four long tiring years. Gilad waited for four long years, and he is still waiting, he is waiting for those who have sent him," Noam Shalit said.
"He is waiting for his commanders, waiting for the prime ministers, defence ministers, waiting and expecting but they don't answer. Instead he hears, at least we hear, I don't know if he can hear, many excuses and scholarly explanations."
Stepping up pressure on Benjamin Netanyahu to agree to a deal, Shalit's family said it would camp indefinitely outside his official residence on July 8, two days after he is due to meet Barack Obama, the US president, in Washington DC.
Shimshon Libman, the head of the public campaign to get Gilad Shalit freed, said that the soldier's release is an "important value" for Israelis.
"What we are trying to ask for the last four years is to release Gilad Shalit back home. We believe that this is a very important value in our life in Israel," he said.
Shalit, now 23, was captured by Palestinian fighters who tunnelled from the Gaza Strip into southern Israel in June 2006.
Israel and Hamas, the Palestinian faction which now governs the enclave, have failed to agree terms of a swap in which around 1,000 of the 7,000 Palestinian prisoners held in Israeli jails would be released in exchange for Shalit.
Hamas had accepted that some prisoners would be exiled but wanted them to be able to choose their destinations, according to officials familiar with the German-mediated negotiations.
Sami Abu Zuhri, the Hamas spokesperson in Gaza, blamed Netanyahu's government for the failure of the prisoner's swap negotiations.
"There are no updates at the moment in the Shalit case. We would like to emphasise to Shalit's family and all the interested parties that Netanyahu and his government are the ones responsible for the failure of the prisoners swap negotiations," he said.
"Several times we had reached understandings that could have resulted in the sealing of the deal, but Netanyahu would back down in the last moments which ultimately led to the failures of the negotiations."