(CNN) -- The Israel Defense Forces said Wednesday it intercepted an Iranian shipment of "advanced" weapons bound for "terrorist organizations" operating in Gaza.
The Israeli navy stopped a Panamanian-flagged civilian cargo ship and boarded the vessel, the IDF said.
The weapons found were identified as Syrian-manufactured surface-to-surface rockets, IDF spokesman Lt. Col. Peter Lerner said.
It was an Iranian shipment headed for Gaza, the IDF said, citing intelligence.
Tehran offered no immediate comment on the incident. According to state media in Iran, military officials denied the reports.
"This allegation is merely based on repetitious and baseless fabrications of the Zionist media," said Hossein Amir Abdollahian, the deputy foreign minister for Arab and African Affairs.
The boarding took place in international waters about 1,000 miles (1,600 kilometers) off the coast of Eilat, Israel, between Sudan and Eritrea in the Red Sea, Lerner said.
Asked why Iran didn't try to send its own missiles to Gaza, the IDF spokesman said Tehran was doing everything possible to cover up its role in the shipment of weapons.
"The IDF will continue to operate against the Iranian attempts to arm regional terrorist organizations, who intend to continuously ignite our borders," Lerner said.
Israeli Prime Minister Benjamin Netanyahu said the weapons shipment was organized by Iran.
"At a time when it is talking to the major powers, Iran smiles and says all sorts of nice things, the same Iran is sending deadly weapons to terrorist organizations and is doing so via a ramified network of secret operations in order to send rockets, missiles and other deadly weapons that will be used to harm innocent citizens," Netanyahu said in a statement.
A spokesman for Gaza's interior ministry said the Israeli action was merely a justification for an ongoing blockade around Gaza.
"The Palestinian resistance is not naive to send this amount of weapons through the sea while it is totally under siege in the Gaza strip," spokesman Islam Shahwan said.
Earlier Wednesday, the IDF reported that it stopped two suspects affiliated with Hezbollah from planting a bomb near the Israel-Syria border.
CNN's Hamdi Alkhshali contributed to this report.