The US Navy has intercepted a shipment of Iranian-made and designed weapons bound for the Houthi rebels in Yemen, the US Central Command announced on Thursday.

Centcom said the operation occurred on Sunday, February 9.

The USS Normandy, while conducting maritime security operations in the Arabian Sea, “boarded a dhow vessel in accordance with international law and discovered a large cache of weapons”.

An image of the vessel boarded by the US Navy which was discovered to be carrying a large cache of weapons.

It said the weapons seized included "150 Dehlavieh anti-tank guided missiles” and “other weapons components seized aboard the dhow were of Iranian design and manufacture".

The US Navy boarded a boat in the Arabian Sea on Sunday and found a large shipment of Iranian weaponry being sent to Yemen#Iran #Yemen pic.twitter.com/CdLPV6721b — CNW (@ConflictsW) February 13, 2020

They included “Iranian surface-to-air missiles, Iranian thermal imaging weapon scopes, and Iranian components for unmanned aerial and surface vessels, as well as other munitions and advanced weapons parts".

The Yemeni military and independent observers have noted that the Houthis have been more sophisticated and deadlier weapons in recent attacks.

A report released by the data firm IHS Markit on Thursday said the rebels were increasingly relying on drones to carry out attacks after a marked improvement in their unmanned aerial vehicle technology.

"No other known non-state armed group across the Mena region and beyond has demonstrated the same level of UAV technological sophistication," the company said in a report.

“The Houthis' rapid adoption and improvement of this technology, almost certainly with Iranian assistance, is a strong indicator that Iran can transfer similar capabilities to some Shiite militias in Iraq and to Hezbollah in Lebanon,” it said.

A report by a UN panel of experts this month noted the technical similarities between weapons seized en route to the rebels and those manufactured in Iran. The Houthis last year intensified aerial attacks on Saudi Arabia using two new weapon systems – a new type of Delta-design drone and a new land attack cruise missile model, the panel said.

IHS Markit said 68 per cent of known Houthi attacks between January and October were conducted using drones and 32 per cent with ballistic missiles.

The UN Security Council has imposed since April 2015 an embargo aimed at blocking weapons to military groups in Yemen.

At least four times since then, the US Navy has intercepted weapons it says were heading to the Houthi rebels.

The previous seizure on November 25 included "sophisticated weapons, sophisticated components of anti-ship cruise missiles, land-attack cruise missiles, air-defence missiles, and anti-tank missiles", the US Special Envoy for Iran Brian Hook said.

"The weapon components comprise the most sophisticated weapons seized by the US Navy to date during the Yemen conflict," Mr Hook told a press briefing a day after the seizure.

Military commanders in Yemen told The National this month that the rebels were suddenly using much more lethal weaponry after four years in which their firepower had weakened.

These include multi-barrel machineguns with larger calibre, more advanced Grad rockets and more destructive bombs, according to Col Abdul Basit Al Baher, army spokesman in the southern city of Taez.

Rebel snipers had also improved their ability to target government forces. “Their snipers shoot at night and within 2,000 to 2,500 metres," he said.