The parents of an Israeli soldier held by Palestinian militants have asked Israel's top court to delay opening border crossings with the Gaza Strip -- for as long as their son remains in captivity.

Corporal Gilad Shalit's parents on Saturday petitioned Israel's Supreme Court to block implementation of a truce that calls for Israel to begin easing a blockade on Gaza Sunday if a cease-fire holds.

The petition includes a letter written by Gilad Shalit and delivered to his family two weeks ago by the foundation led by former U.S. President Jimmy Carter.  In that letter, the soldier pleads for his life and urges his government not to abandon him.

Shalit was captured by Hamas militants in a cross-border raid two years ago.  Israel has refused Palestinian demands for a prisoner swap that would include his release.

An Egyptian-mediated truce in Gaza took effect Thursday and has been holding since.  It calls for ending the nearly daily Palestinian rocket attacks on southern Israel and the retaliatory Israeli military raids on Gaza.

Both sides have voiced doubt about how long the cease-fire will last

Some information for this report provided by AFP, AP and Reuters.