LONDON (AP) — Britain says it has for the first time presented evidence that Iran is supplying advanced weapons to the Houthi rebels in Yemen, after finding images of tests conducted at the headquarters of the Revolutionary Guards in Tehran on the hard drive of an unmanned aircraft seized by the Royal Navy.

Personnel from the British ship HMS Montrose seized the unmanned quadcopter along with a shipment of missiles and missile parts in February last year when they stopped and searched a number of fast-moving skiffs in the Gulf of Oman. The weapons and other evidence were presented to the United Nations as linking Iran to violations of Security Council resolutions barring weapons shipments to the Houthis, Britain’s Ministry of Defense said Monday in London.

“This is the first time we have been able to present evidence to the U.N. that indicates a direct link between the Iranian state and the supply of these weapons,” a ministry official said, speaking on condition of anonymity in line with departmental policy.

The UN has prohibited weapons transfers to the Houthis since 2014, when the rebels descended from their northern stronghold, toppled the internationally recognized government of Yemen and seized the capital, Sanaa. Iran has long denied arming the rebels.

The commercial quadcopter seized by the Royal Navy is designed for reconnaissance flights, the ministry said.

Investigators were able to decrypt the data on the aircraft’s internal memory, which hadn’t been wiped. That’s where they discovered the records of 22 test flights conducted at the Revolutionary Guards’ aerospace headquarters in western Tehran, the ministry said.

The drone was in the same shipment as a number of surface-to-air missiles and components for Iranian Project 351 land attack cruise missiles.

The discovery adds to a growing body of evidence of Iranian interference in the conflict in Yemen, which has spawned one of the world’s worst humanitarian crises.

Western nations, U.N. experts and others have traced Houthi weaponry ranging from night-vision scopes, rifles and missiles back to Tehran.

Most recently, French naval forces in the Gulf of Oman in January seized thousands of assault rifles, machine guns and anti-tank missiles coming from Iran and heading to the Houthis.

In November, the U.S. Navy announced that it had found 70 tons of a missile fuel component hidden among bags of fertilizer aboard a ship sailing to Yemen from Iran.

“Once again the Iranian regime has been exposed for its reckless proliferation of weapons and destabilizing activity in the region,’’ said Tariq Ahmad, Britain’s minister of state for the Middle East. “Iran’s sustained military support to the Houthis and continued violation of the arms embargo has stoked further conflict and undermined U.N.-led peace efforts.”

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Associated Press Writer Samy Magdy in Cairo contributed.