The outpouring of support for the family of Staff Sgt. Gilad Schalit was part of a 12-day protest march across Israel, launched last week to pressure Israel's government to conclude a prisoner swap deal for his release.
In a related bid to draw attention to the plight of the soldier, renowned conductor Zubin Mehta planned to lead the Israel Philharmonic Orchestra in a special concert near the Gaza border. Mehta said he hopes the concert will inspire Gazans to pressure the Hamas government to allow the Red Cross to visit the soldier for the first time.
Noam Schalit, the soldier's father, told the crowd at a square in downtown Tel Aviv that the large turnout would push the government to make a deal to free his son.
"Look at this massive wave of citizens marching with us in the thousands, in the tens of thousands," he said. "The release of Gilad and his return home is not just the wish of our family, it is the will of the people."
The days of mass protests have put heavy pressure on Prime Minister Benjamin Netanyahu to strike a deal with Hamas - which Israel shuns as a terrorist group.
Netanyahu said last week he has agreed to trade 1,000 Palestinian prisoners for Schalit, but said he would not accept the group's demand to include senior militants convicted in deadly attacks against Israelis. Like his predecessor, Ehud Olmert, Netanyahu fears convicted killers would return to violence if freed.
Marchers wore T-shirts bearing the soldier's image, and drivers stuck in traffic honked their horns to show support. Soldiers at the Israeli military's headquarters in the city clapped as the march passed by.
Schalit, 23, was seized inside Israel by Hamas-linked militants in June 2006. The militants killed two other crewmen in Schalit's tank. His captors have barred any access to him and released only a brief videotape last year to prove he was still alive.
Schalit's plight has touched the hearts of many in Israel, where military service is compulsory for Jewish citizens and most families have relatives who serve.
"I have a son in the army and I hope that if, heaven forbid, he was captured everything would be done to bring him home," said Etti Danbo, 53, one of the marchers. "Gilad is like my son. He could be anyone's son."
Some families of Israelis killed in Palestinian attacks have called on the government to reject a deal that would free militants convicted of killing Israelis. Danbo said she identified with those bereaved families, but said the victims were dead and "Gilad is still alive."
(Left: On Sunday during a protest outside the home of Hamas leader Mahmoud Al Zahar in Gaza City, Palestinian women held pictures of relatives held in an Israeli jail, urging the militant leadership not to compromise on its demands for hundreds of prisoners in exchange for Schalit.)