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JERUSALEM (AP) — State ceremonies across Israel will commemorate nearly 23,000 fallen soldiers and civilian victims of attacks.

President Shimon Peres has taken the occasion of Israel's memorial day to warn the world not to underestimate the potential threat of Iran's nuclear program.

Israel, like the West, doesn't believe Tehran's claims that its nuclear program is peaceful.

Peres spoke at the opening ceremony of the somber day, which began Sunday night and continues through Monday night. Air raid sirens Monday morning will mark the start of the day's state ceremonies.

Israel's 62nd Independence Day begins at nightfall. On the occasion of that event, U.S. Secretary of State Hillary Rodham Clinton said the U.S. "will not waver in protecting Israel's security."