The Israeli navy yesterday seized a ship carrying what defence officials said was five hundred tons of Iranian-supplied weapons bound for Hizbollah guerrillas in Lebanon, including Katyusha rockets that could be used in the event of renewed Israel-Hizbollah hostilities.

Army spokeswoman Maj Avital Leibovitch said it was the largest weapons seizure ever by the Israeli military. Israeli vessels in the Mediterranean stopped the ship, the Francop, a commercial vessel flying an Antiguan flag, in international waters one hundred miles west of the Israeli coast and searched its cargo, army officials said. After discovering weapons concealed in containers, they escorted the ship to the Israeli port of Ashdod, where troops began unloading it.

Defence Minister Ehud Barak said the seizure stopped the weapons from going to "the northern sphere of terrorism", a reference to Hizbollah, which fought the Israeli army to a stand off in 2006, firing 4,000 rockets at the Jewish state. But Israeli officials produced no immediate proof that the weapons came from Iran or were bound for Hizbollah. The Lebanese fundamentalist group declined to comment yesterday on the seizure, while Syria denied the boat was carrying Iranian weapons to Syria, which Israel alleges supplies Hizbollah with weaponry from its territory.

Israeli navy rear-admiral Roni Ben-Yehuda said the boat had picked up the cargo of weapons in Egypt, but added, "We are sure that the crew and even the Egyptians did not know what was being loaded onto it."

Analysts said the interdiction would not have much impact on the long-term balance of power between Israel and Iran or Israel and Hizbollah. "It's important tactically but it's not as if we've discovered something we didn't know about here," said Yossi Alpher, former director of the Jaffee Center for Strategic Studies.

Israel sees both Hizbollah and the Palestinians' Hamas movement as proxies Tehran uses to wage indirect war against the Jewish state. On Tuesday, the Israeli army intelligence chief, Amos Yadlin, said Hamas had tested a missile with a range of 60k