Hundreds of crates - some opened to reveal rockets, mortar shells, and boxes of grenades and bullets - lined the dock in Israel's port of Ashdod hours after the predawn naval operation in the Mediterranean Sea near Cyprus.

By evening, Israeli forces were still unloading the 40 containers of armaments reported found aboard the Antigua-flagged vessel Francop, which remained under guard.

The weapons, including hundreds of Grad-type Katyusha rockets, were concealed beneath civilian goods and enclosed in a plastic material that can fool electronic scanners, Israeli officials said.

Rear Adm. Roni Ben-Yehuda, the deputy Israeli navy commander, said the cache was "a drop in the ocean" of arms being shipped to Hezbollah, the Islamic militia that pelted Israel with rockets during a monthlong 2006 war.

Israeli officials made the most of the seizure to bolster their assertion that Iran, with Syria's complicity, is arming enemies of the Jewish state, in violation of U.N. Security Council resolutions that bar Iran from exporting weapons. Iran and Syria reject the allegation.

"Today the whole world can see the large gap between Syria and Iran's statements and their actual activities," Israeli President Shimon Peres said.

Captured containers on display in the port bore Iranian shipping codes in English - IRISL on one side, I.R. Iranian Shipping Lines Group on the other.

Lt. Col. Avital Leibovich, a military spokeswoman, said a cargo certificate gave the containers' origin as the Iranian port of Bandar Abbas. Ben-Yehuda said the shipment was headed for Latakia, Syria's principal port.

The certificate was not shown to reporters. Israeli officials offered no evidence that Hezbollah was the weapons' intended recipient, except to note that Israeli intelligence previously identified Latakia as a conduit for armaments sent by land to Hezbollah's strongholds in Lebanon.

Syrian Foreign Minister Walid Moallem, during a visit to Iran, acknowledged yesterday that the vessel had been sailing to Syria but denied that any weapons were aboard, according to Iran's Mehr news agency. Iran denied sending weapons. Hezbollah issued no response.

Israeli officials said the Francop picked up the weapons in Damietta, Egypt.

An official of United Feeder Services, the Cyprus-based shipping company that leased the vessel from German owners, told Israel's Ynet online news agency that the company did not know what was inside the containers and was not allowed to inspect them before the ship left Egypt.

Israeli officials said they believed that Egypt's government and the vessel's captain and crew were unaware of any weapons. The officials suspect the weapons were smuggled to Damietta on several other vessels from Iran via the Persian Gulf, Red Sea, and Suez Canal.

Ben-Yehuda would not say whether Israel had prior intelligence about the cargo. He said Israeli and Western intelligence agencies keep constant tabs on suspected smuggling lanes.

Israeli leaders gave no hint in their public comments that they were contemplating military action in response to the alleged smuggling attempt. The Israel-Lebanon border has been largely quiet since the 2006 war, though Israel has warned that Hezbollah has been rearming and now has about 40,000 rockets.