JERUSALEM (CNN) -- The parents of an Israeli soldier held captive for nearly two years petitioned Israel's High Court Sunday to compel the government to explain why a cease-fire with Hamas did not include the release of their son.
Cpl. Gilad Shalit was seized in June 2006 in a raid into Israel by militants of Hamas, the radical Islamic group that Israel and the United States consider a terrorist organization.
Shalit's parents also made public a letter they received from him earlier in June in which he asked the government "not to neglect the negotiations for my release."
The petition, which names Cpl. Shalit as the first petitioner, is filed against Prime Minister Ehud Olmert and his senior ministers.
It asks the court to instruct the government to explain why the agreement that includes the opening of the border crossings was not conditioned upon Shalit's release or his transfer to Egypt.
Israel has repeatedly said that last week's truce with Gaza's Hamas leaders was a first step toward a broader cease-fire agreement that must include Shalit's release.
Israel's point man for the negotiations to release Shalit, Ofer Dekel, heads to Cairo on Tuesday, an Israeli official said. Olmert is also going to the Egyptian capital on Tuesday for an official visit with Egyptian President Hosni Mubarak.
Olmert held "security consultations" with Dekel, Defense Minister Ehud Barak, and others on Sunday regarding how to expedite the negotiations on Shalit's reaction.
Shalit's parents said they saw the letter as their moral power of attorney to file the petition in their son's name.
His father, Noam, confirmed to CNN that the letter was in Shalit's handwriting and appeared to have been written recently.
The letter opens with the greeting, "Dear Mom and dad and family."
"I miss you terribly. Two long and hard years have passed since I was separated from you and had to live in captivity. I continue to suffer from health and emotional difficulties and suffer many periods of depression.
"As in my last letters, I hope that your health and emotional condition has not suffered since you began to live without me. I still think and dream of the day when I will go free and see you again. I still have hope that that day is close, but I know that it doesn't depend on me or you.
"I appeal to the government not to neglect the negotiations for my release.
"I miss you, Gilad."
The letter was delivered to the parents through a representative of former U.S. President Jimmy Carter who held a controversial meeting with the Hamas leader, Khaled Meshaal, in April 2008.
Meshaal promised Carter then that Hamas would allow Shalit to send a message to his parents, Noam and Aviva. Carter also asked Hamas to release Shalit, Meshaal said after the former president's visit, but the request was rejected.
In August 2007, Meshaal told CNN Shalit was alive and well. He told CNN Senior International Correspondent Nic Robertson that Hamas had been negotiating for the release of Palestinian prisoners in exchange for Shalit through an Egyptian intermediary.
Shalit was 19 when he was captured on June 25, 2006, by Palestinian militants who tunneled into Israel and attacked the Israeli army's Kerem Shalom outpost near the Gaza-Israel-Egypt border, according to Israel Defense Forces.
Two other Israeli soldiers were killed in the assault.
Hamas is demanding the release of Palestinian prisoners from Israeli jails in exchange for the return of Shalit. Egypt is mediating between the two sides.
Hamas released an audio message reportedly from Shalit in June 2007 on the first anniversary of his capture.
Weeks after Shalit's capture, Hezbollah militants launched a cross-border raid from Lebanon north of Israel and kidnapped two Israeli soldiers, touching off a war between Israel and Hezbollah.