It's time for the United States to hold Iran accountable.

Iran's Revolutionary Guards have started using a new route across the Gulf to funnel covert arms shipments to their Houthi allies in Yemen's civil war, sources familiar with the matter have told Reuters.

In March, regional and Western sources told Reuters that Iran was shipping weapons and military advisers to the Houthis either directly to Yemen or via Somalia. This route however risked contact with international naval vessels on patrol in the Gulf of Oman and the Arabian Sea.

For the last six months the Islamic Revolutionary Guards Corps (IRGC) has begun using waters further up the Gulf between Kuwait and Iran as it looks for new ways to beat an embargo on arms shipments to fellow Shi'ites in the Houthi movement, Western and Iranian sources say.

Using this new route, Iranian ships transfer equipment to smaller vessels at the top of the Gulf, where they face less scrutiny. The transhipments take place in Kuwaiti waters and in nearby international shipping lanes, the sources said.

"Parts of missiles, launchers and drugs are smuggled into Yemen via Kuwaiti waters," said a senior Iranian official. "The route sometimes is used for transferring cash as well."

The official added that "what is especially smuggled recently, or to be precise in the past six months, are parts of missiles that cannot be produced in Yemen".

Cash and drugs can be used to fund Houthi activities, the official said.

Kuwait on Wednesday denied Iran was using its waters to smuggle equipment to Houthi forces in Yemen.

A foreign ministry statement said the country's waters were under the total control of the Kuwaiti navy and coast guard and there were no reports of suspicious movements at sea.

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