ABU DHABI, United Arab Emirates (AP) — Officials in a Saudi-led coalition now battling Shiite rebels for control of a crucial port in Yemen on Tuesday displayed weapons captured on the battlefield that they say show Iran is arming the insurgents.

Iran has long denied arming the rebels, known as Houthis, despite reports by the United Nations, Western countries and outside groups linking it to the rebels’ arsenal.

Weapons shown to reporters in Abu Dhabi and later at an Emirati military base on a government-sponsored tour included drones, a sniper rifle, roadside bombs disguised as rocks and even a “drone boat,” which had been filled with explosives that failed to detonate.

The officials showed Iranian-labeled components inside of equipment that they said was used to produce and load fuel for the rockets the rebels have fired across the border at Saudi Arabia. They also displayed images allegedly showing Iranian officials building components for the “drone boat.” The officials said such weapons threaten both coalition forces and civilians.

“Unsurprisingly, there are advanced military components in the Houthi militia’s hands,” Talal al-Teneiji, an Emirati Foreign Affairs Ministry official, told The Associated Press. “We took time to inspect and disassemble these to figure out the source … and we can say that these elements are military-grade materials imported from Iran to the Houthi militias.”

Iran’s mission to the United Nations did not immediately respond to a request for comment Tuesday.

The rare show-and-tell by the Saudi-led coalition comes as the United Arab Emirates leads Yemeni forces in an offensive seeking to capture the Red Sea port city of Hodeida.

Their campaign has been criticized by international aid groups, which fear a protracted fight could force a shutdown of the port and potentially tip millions into starvation. Some 70 percent of Yemen’s food enters via the port, as well as the bulk of humanitarian aid and fuel supplies. Around two-thirds of the country’s population of 27 million relies on aid and 8.4 million are already at risk of starving.

The Houthi-controlled port has remained open, as the main battle Tuesday was around the city’s airport, to the south.

Some of the weapons shown have previously been described by UN weapons experts and an independent group called Conflict Armament Research, which gained access to the materiel through the UAE’s elite Presidential Guard. Among them were roadside bombs disguised as rocks that the research group has said bear similarities to others used by Hezbollah in southern Lebanon and by other Iran-backed fighters in Iraq and Bahrain, suggesting at the least an Iranian influence in their manufacture.

Already, the Saudi-led coalition has disarmed between 20,000 to 30,000 land mines and bombs, most laid indiscriminately by the Houthis, al-Teneiji said.

Other weapons on display Tuesday included a .50-caliber sniper rifle and mines. Officials also displayed a series of drones they said showed a growing sophistication by the insurgents, starting first with styrofoam models that could be built by hobby kit to one captured in April that closely resembled an Iranian-made drone.

Those advanced drones have been flown into the radar arrays of Saudi Arabia’s Patriot missile batteries, according to Conflict Armament Research, disabling them and allowing the Houthis to fire ballistic missiles into the kingdom unchallenged. Iran has been accused by the US and the UN of supplying ballistic missile technology to the Houthis, something Tehran denies.

At a military base, the officials showed what they described as “dual-use” equipment that they believe was used to fuel Badr rockets, gear which they seized from smugglers in Yemen’s central Marib governorate. Inside one piece of equipment a component bore the name of Shokouh Electric, an Iranian firm. Another piece of the equipment bore the Farsi name and address of Mashal Kaveh, another Iranian company.

The Saudi-led coalition officials spoke on condition of anonymity to discuss intelligence matters. The AP could not immediately reach the Iranian companies for comment, but Iran has mocked previous show-and-tell events by Saudi and American officials.

The officials also shared black-and-white images they said came from the “drone boat” that failed to explode. They said the pictures and associated data from the boat’s computer showed Iranians building components for the boat’s guidance system in eastern Tehran, with a hat in the background of one picture bearing the symbol of Iran’s Islamic Revolutionary Guard.

They said those involved in building the boat’s components likely believed it would be destroyed in the blast, so they didn’t wipe the computer’s hard drive. But perhaps more telling in Yemen’s long, complicated war was the fact that the boat itself actually came from the UAE, which had originally given it to Yemeni government forces.