Elite Iranian troops helped Hezbollah fire a sophisticated radar-guided missile at an Israeli warship, Israeli officials said Saturday, describing an apparent surprise blow by militants who had been using only low-tech weapons.

Iran denied that it had any troops in Lebanon. (Full story)

Israel initially believed that an aerial drone armed with explosives hit the warship, but it became clear that Hezbollah had used an Iranian-made C-802 missile to strike the vessel late Friday, an Israeli intelligence official said on condition of anonymity because of the sensitive nature of the information.

Iran's embassy in Beirut issued a statement late Saturday that called the Israeli allegations "meaningless."

It is "an attempt to escape reality with the aim of covering up (Israel's) inability to confront the Lebanese nation and resistance," the statement said.

One Israeli sailor was killed and three were missing after the attack. The ship was returning to its home port in Israel, the army said.

About 100 fighters from Iran's Revolutionary Guard helped import, equip and fire the missile at the Spear, a missile ship cruising off the coast of Lebanon, which is under an Israeli naval blockade, Israeli officials said.

President Mahmoud Ahmadinejad condemned Israel's military offensive in Lebanon, telling state television "the Zionist regime behaves like Hitler," state television reported.

Hezbollah is widely believed to have been trained, funded and guided by the Revolutionary Guard since the militant group was founded during Israel's 1982 invasion of Lebanon. The Islamic republic's elite corps of more than 200,000 fighters is independent of the regular armed forces and directly controlled by Iran's supreme leader.

"We can confirm that it (the ship) was hit by an Iranian-made missile launched by Hezbollah. We see this as a very profound fingerprint of Iranian involvement in Hezbollah," Brig. Gen. Ido Nehushtan told The Associated Press.

The Shiite militant group had been firing only highly inaccurate Katyusha rockets at Israeli targets. Israel appeared surprised that the guerrilla group had high-tech weapons.

Israeli officials speaking on condition of anonymity because of the sensitivity of the information said that Hezbollah also has Iranian-made drones that are more accurate than missiles, as well as longer-range projectiles that could hit Tel Aviv, Israel's commercial hub.

An Israeli military official said the Spear's missile detection and deflection system was not on during the attack, apparently because the sailors did not anticipate such an attack.

The military official said the ship is one of the most technologically advanced in the Israeli fleet, boasting an array of high-tech missiles and a system for electronically jamming incoming missiles and other threats.

Nehushtan said another Hezbollah radar-guided anti-ship missile hit and sank a nearby Cambodian merchant ship around the time the Spear was struck. Twelve Egyptian sailors were pulled from the water by passing ships, Brig. Gen. Noam Fieg said.

Nehushtan said the body of one of the four Israeli soldiers missing in the attack was found on the damaged warship. Other Israeli military officials said two bodies had been found.

Israel launched an offensive after Hezbollah guerrillas crossed the Israel-Lebanon border on Wednesday and captured two Israeli soldiers. Israel has bombarded Lebanon's airport and main roads in the most intensive offensive against the country in 24 years, while Hezbollah has launched hundreds of rockets into Israel.