Israel was Saturday night unloading more than 100 containers from the Klos-C — the ship it seized Wednesday in the Red Sea and brought into Eilat port on Saturday — in a sensitive operation expected to last late into Sunday.

Israeli leaders and security chiefs have said the Panama-registered cargo ship was carrying advanced Syrian-made missiles shipped by Iran intended for terror-group recipients in Gaza. Military sources said Saturday night, however, that they believed other weaponry might also be hidden in the cargo.

The Kloc-C was loaded with over 100 containers, which were being brought by truck from the ship to a nearby Israel Navy base, where they were being unloaded under strict security by elite IDF units and other experts. Officials were concerned to ensure that any explosive materials in the containers be handled safely.

The unloading operation was scheduled to finish on Sunday afternoon. Prime Minister Benjamin Netanyahu scheduled a press conference in Eilat on Monday to show and detail the findings.

IDF Chief of Staff Lt.-Gen. Benny Gantz met with soldiers who participated in the raid and hailed their success on Saturday evening. During the meeting, at a naval base in Eilat, Gantz told the soldiers that the struggle against the empowerment of terrorist groups and the effort to keep them from strategic arms hadn’t ended with their return home to Israel.

“This was a long and complicated mission, but there will be many more missions,” Gantz said, adding that every one of the rockets aboard the ship had an intended address in Israel.

In interviews over the weekend, Netanyahu blamed Iran for the shipment, and said this confirmed Tehran’s ongoing orchestration of terrorism. Israel had caught Iran delivering “missiles to terror groups,” Netanyahu told Channel 10 News. “This is the true face of Iran.”

He told Channel 2 in an interview that Iran was “relentlessly” arming terror groups. It was presenting a different “face to the world,” but had not genuinely changed “by one iota” since the election of Hassan Rouhani as president last year, he said, and must be denied a nuclear weapons capability.

The Klos-C, now flying both an Israeli flag and the Israel Navy flag, entered the port of Eilat Saturday afternoon with an Israel Navy escort after a voyage of three-and-a-half days following Israel’s interception of the ship off the coast of Sudan early Wednesday.

Its Croatian crew was initially held for questioning, reports said. IDF sappers were standing by on shore to search the ship for booby traps and handle any explosives in the Klos-C’s hold.

Masked soldiers of the crack Shayetet 13 naval commando unit were visible standing on the decks of the Klos-C as it docked.

Masked Shayetet 13 soldiers standing on the bow of the Klos-C as it docks in Eilat on Saturday, March 8, 2014. (screen capture: Ynet)

Masked Shayetet 13 soldiers standing on the bow of the Klos-C as it docks in Eilat on Saturday, March 8, 2014. (screen capture: Ynet)

The cargo ship entered port just after 4:30 p.m., with the INS Hanit cruising along its port side. The INS Hetz sailed into port shortly thereafter. Civilian craft welcomed the ships to Israeli waters with a chorus of horn-blowing, Israel Radio reported.

The Klos-C is expected to be released with her Turkish captain and her crew in the coming days after the weapons in its hold are offloaded.

Israeli commandos boarded the Panamanian-flagged ship early on Wednesday in the Red Sea, and found it to be carrying an Iranian arms shipment headed for the Gaza Strip, Israel’s military said. The consignment had been tracked by Israeli intelligence for months, officials said.

The army said Wednesday that soldiers carried out a preliminary inspection of the ship and found several dozen advanced Syrian M-302 missiles, with a range of up to 200 kilometers (125 miles) and a payload of up to 170 kilograms (375 pounds). The missiles were hidden in shipping containers also carrying sacks of concrete with Iranian markings.

The INS Hetz sails into Eilat with all hands on deck on Saturday, March 8, 2014. (screen capture: Ynet)

The INS Hetz sails into Eilat with all hands on deck on Saturday, March 8, 2014. (screen capture: Ynet)

Israel and the US coordinated intelligence and military activities leading up to Israel’s seizure of the Klos-C off the coast of Port Sudan, US Ambassador to Israel Dan Shapiro and the State Department said Wednesday.

After consultations between American and Israeli officials, it was decided that Israel would act against the vessel, Shapiro told Israel Radio, even though the Pentagon had already drafted plans to intercept the ship.

Israel’s capture of the Klos-C followed intensive intelligence work, officials said, with the missile shipment tracked for months from Damascus to Iran and from there to Iraq before it was intercepted en route to Gaza.

Times of Israel staff contributed to this report.