Israel said it intercepted a ship Wednesday carrying an Iranian shipment of advanced rockets bound for Palestinian militants, claiming it proved Tehran could not be trusted in international nuclear talks.
The announcement came hours after Israel said it struck two Hezbollah fighters as they tried to plant a bomb near the Syrian-Israeli frontier and just over a week after Israel reportedly bombed the Iran-backed group inside Lebanon for the first time since 2006.
Israel has long accused Iran and Syria of providing military aid to Hezbollah and to Palestinian militant groups, and the military spokesman's office tweeted that the ship was carrying weapons "capable of striking anywhere in Israel".
Iran's Arabic-language Al-Alam television channel quoted a military official in the Islamic republic as denying the Israeli report, calling it "totally without foundation".
Israel latched onto the weapons shipment to chide Western powers for negotiating with Tehran over its nuclear programme.
"While Iran is conducting these talks, smiling to the international community, it continues to arm terrorist groups, continues to perpetrate terrorism around the world," Prime Minister Benjamin Netanyahu, currently in the United States, said in a statement.
The military said the Syrian-made weapons aboard the "Klos-C" were shipped overland to Iran and then onward towards Gaza by sea before being intercepted in the Red Sea between Sudan and Eritrea.
Lieutenant Colonel Peter Lerner told reporters that "dozens" of surface-to-surface M302 Syrian-manufactured rockets were found aboard the ship, adding that the crew had "fully cooperated".
Lerner said Israel had followed the shipment for "several months" and that the military knew "for a fact" the Iranians were behind it.
Militants in Gaza, which is governed by the Palestinian Islamist movement Hamas, have fired dozens of rockets at the Jewish state since the beginning of the year, and Israel has responded with air strikes killing both militants and civilians.
Defence Minister Moshe Yaalon said the weapons were destined for Islamic Jihad, a smaller Islamist movement which had become "the armed wing of Iran in the Gaza Strip".
Hamas, meanwhile, was "hesitant for the moment to link itself with Iran again", he said.
- 'World powers wrong on Iran' -
His deputy, Danny Danon, said the shipment proved that world powers were wrong to grant Iran limited sanctions relief in return for it curbing or freezing its nuclear activities under an interim agreement clinched in November.
Israel, the region's sole if undeclared nuclear-armed state, has long accused Iran of seeking to develop atomic weapons, charges vehemently denied by Tehran which insists its nuclear programme is entirely peaceful.
The P5+1 -- the United States, Britain, France, Russia and China plus Germany -- are set to hold another round of nuclear talks with Iran aimed at a comprehensive agreement later this month.
The ship interception report came just hours after the Israeli army claimed to have hit two Hezbollah fighters along the Syrian border with the annexed Golan Heights, without specifying what weapons were used or whether the targets were killed.
Hezbollah did not immediately comment, but Syria accused Israel of firing four rockets from the Golan, violating a ceasefire in place since the 1970s.
Last month Israeli warplanes reportedly bombarded Hezbollah positions inside Lebanon for the first time since the 2006 war, prompting a threat of retaliation.
Israel is bent on halting any transfer of weapons to Hezbollah, which has sent thousands of fighters across the border to aid Syrian President Bashar al-Assad's regime as it battles Sunni-led rebels.
In May 2013, Israel launched two raids targeting what it said were arms convoys near Damascus destined for Hezbollah, and in November there were reports of an Israeli strike against a Syrian air base where missiles for Hezbollah were located.
Syria has long provided arms and other aid to Hezbollah, and served as a conduit for Iranian military aid to the movement.
Israel has accused Iran of trying to establish similar supply lines by sea to Gaza.
Israeli commandos in 2011 seized a ship carrying what Israel said were Chinese-made arms from Iran bound for Gaza militants. And in 2002, Israel seized 50 tonnes of weapons from the vessel "Karine A" on its way to Gaza.