Khaled Meshal, the Damascus-based head of the Hamas politburo, responded yesterday to rising public pressure in Israel to free Gilad Shalit by threatening that his organization would kidnap more Israeli soldiers and raise the price it demanded in a prospective prisoner swap.

"Shalit will not be alone. We will continue to capture soldiers and officers of the enemy until it frees all our prisoners. This is my message," Meshal said in a speech to students in the Syrian capital.

"Israel only understands the language of force," Meshal continued. "Our brothers ... will succeed in repeating the experience of the capture of Zionist soldiers."

Meshal said the German mediator negotiating a prisoner exchange had on several recent occasions offered him to renew talks with Israel, but that he had refused because their terms did not meet his demands. "We are telling the mediators that we would like to resume negotiations, but we will not give up our claims," Meshal said.

The Hamas political leader accused "the Israeli leadership of having obstructed the prisoner exchange and of going back on its proposal under pressure from the U.S. administration."

Shalit, Meshal said, would not be freed until Prime Minister Benjamin Netanyahu responds to "our just demands."

Meanwhile, Shalit's grandfather Zvi called on Netanyahu yesterday to cut short his family's protest march to Jerusalem by making a clear declaration of his intent to strike a deal to bring the soldier home.

"I ask the prime minister to give an explicit declaration that Gilad will be freed, and thereby cut short this long, exhausting march," Zvi Shalit said at a demonstration the family had organized in the Haifa suburb of Kiryat Motzkin to mark the end of the procession's second day. "I don't understand why he's waiting until we reach Jerusalem to meet with the family. I am asking him to state his intentions now."

Thousands of supporters took part in the rally to free Gilad Shalit, including many who had marched alongside the family the entirety of yesterday's route from Kibbutz Lohamei Hageta'ot to Kiryat Motzkin.

Noam Shalit, the captive soldier's father, told demonstrators, "We expected hundreds of people, and thousands came. It encourages and strengthens us... I call on the entire nation to join us for the rest of this march."

Yossi Zur, who lost his son Assaf in a 2003 suicide bombing in Haifa, said, "I don't know about any exchange in the works, but I've come here to mark four years since Gilad's abduction."

Zur said bereaved families like his have stated on a number of occasions that they are in favor of a prisoner swap, but not at any price and not one that includes the release of terrorists convicted of murder.

Activists for Shalit's release also expressed satisfaction with the massive show of support. "It feels like Independence Day - we're really seeing and feeling the support of the wider public. Dozens of rest and water stations were set up spontaneously," said Shimshon Liebman, who heads the campaign. "We'll continue to Jerusalem in the hope that this atmosphere will influence the prime minister."

Rabbi Yosef Yashar, the chief rabbi of Acre, called on Netanyahu to display leadership by completing a prisoner swap with Hamas.

"I'm ashamed that Gilad's father and mother have to wage this campaign alone," he said. "Gilad is our soldier, a soldier of the IDF and of all of Israel. We beg the prime minister - Gilad's life is far more valuable than those of these despicable Hamas prisoners, even if they have blood on their hands. Show some leadership."