Iran, considered the world’s leading state sponsor of terrorism, has increased its shipments of military supplies to Shiite Houthi rebels fighting a Saudi-led and U.S.-assisted coalition in Yemen, Reuters has learned from Western and Iranian officials on condition of anonymity.

“We are aware of a recent increased frequency of weapons shipments supplied by Iran, which are reaching the Houthis via the Omani border,” a Western diplomat familiar with the conflict told the news outlet, which noted that “three U.S. officials confirmed that assertion.”

“In my mind, the level of Iranian arms smuggling probably doesn’t get the attention it deserves,” added the senior Western diplomat.

There has been a “sharp surge in Iran’s help to the Houthis in Yemen” since May, referring to weapons, training and money, also confirmed a senior Iranian diplomat.

“The nuclear deal gave Iran an upper hand in its rivalry with Saudi Arabia, but it needs to be preserved,” added the diplomat.

One of the American officials revealed that Iran was providing the Houthis in Yemen with “anti-ship missiles, explosives… money and personnel” via neighboring Oman.

“Another regional security source said the transfers included surface-to-surface short-range missiles and small arms,” notes Reuters.

Those revelations come a day after U.S. Army Gen. Joseph Votel, the top American commander in the Middle East, said he suspects the Shiite Islamic Republic was behind the missiles launched twice by Houthi rebels against U.S. ships in the Red Sea last week.

The general’s comments marked the closest a U.S. official has come to directly attributing the recent missile attacks against the American Navy to Iran.

During an event hosted by the liberal think-tank Center for American Progress in Washington, D.C., Gen. Votel said:

I do think that Iran is playing a role in some of this. They have a relationship with the Houthis, so I do suspect there is a role in that.

Gen. Votel also said Houthi-allied  troops loyal to ousted Yemeni President Ali Abdullah Saleh may have played a role as well.

“The Iran-allied Houthis gained a trove of weapons when whole divisions allied to former Yemen President Ali Abdullah Saleh sided with them at the start of the war last year,” points out Reuters.

Although it is unclear what the administration of President Barack Obama would do in retaliation if it confirms that Iran was indeed responsible for the failed missiles attacks against the U.S., the top American general declared:

What we are trying to do is make sure we understand this as much as we can so we can properly attribute what is happening and understand how these attacks are taking place and, more importantly, how the decisions are being made to launch these attacks so we can take action against that.

American officials had so far said the missile launches against U.S. ships were from “Houthi-controlled territory” in Yemen, without specifying who actually pulled the trigger or who exactly was to blame.

Reuters reports:

Much of the recent smuggling activity has been through Oman, which neighbors Yemen, including via overland routes that take advantage of porous borders between the two countries, the officials said.

Oman, considered a strategic U.S. ally in the war-ravaged region, denies that Iranian weapons are being smuggled across its border into Yemen.

A senior Yemeni military source told Reuters that the frequency in arms trafficking had also increased “because Iran feels the Houthis are in a difficult situation and want to show them they’re with them till the end.”

In response to the failed missile attacks on the American Navy, the United States struck Houthi targets with cruise missiles.

Michael Knights, an expert on Yemen’s ongoing war at the Washington Institute for Near East Policy, suggested that attacking U.S. warships has placed the Houthi troops in the same league as Iran’s narco-terrorist proxy Hezbollah, which is based in Lebanon and accused of operating in Yemen.

The Pentagon is still trying to find out if there was an additional missile launch against the United States from Yemen after the American Navy destroyed Houthi radar sites with its cruise missiles.

Yemen’s conflict has been described as a proxy war between regional rivals Shiite Iran and Sunni Saudi Arabia.

The Saudi-led coalition has been targeting the Houthis in an effort to restore the internationally-recognized Yemeni President President Abd Rabbu Mansour Hadi to office.

Meanwhile, the Shiite rebels have been receiving weapons and military support Iran, something that both the Islamic Republic and the Houthis deny.

Citing Pentagon data at the end of August, Fox News found that there have been a total of at least 30 “dangerous” confrontations between the Iranian and American navies in the Persian Gulf so far this year, more than the 24 that took place during all of last year.