The top admiral overseeing US Naval forces in the Middle East, Vice Adm. Brad Cooper, warned Wednesday that the biggest threat to the security of navigation in the Gulf is from Iran.

“The most serious threats that we see do come from Iran. They come in two forms: the growth and capability and numbers of cruise missiles, ballistic missiles and UAVs, as well as their use of proxies in those particular weapons,” said the commander of the US Naval Forces Central Command, US 5th Fleet and Combined Maritime Force (CMF).

Speaking to Al Arabiya in Washington, Cooper pointed to the risks emanating from Iran’s drone program and the technology it provides its regional proxies.

The 5th Fleet commander is also in charge of the CMF, a naval force of 34 member nations operating in the Red Sea, Gulf of Aden, Northern Arabian Sea, Gulf of Oman, Arabian Gulf and Indian Ocean.

In recent years, the force has played a vital role in foiling drug and weapons smuggling.

Last month alone, the US Navy said it seized $85 million worth of heroin from a fishing vessel, making it the biggest illegal drug interdiction in the Middle East by international naval forces this year.

Two days later, the Navy said it seized $10 million (7,200 kg) worth of hashish from another fishing vessel in the Gulf of Oman.

But the US and its allies in the region are also constantly looking out for illicit weapons transfers.

In December, Navy patrol ships said they interdicted a fishing vessel with 1,400 Russian rifles and 226,600 rounds of ammunition. They said the vessel was believed to have been heading to Yemen from Iran.

The Iran-backed Houthi militia in Yemen continues to receive logistical, financial, and military support from Tehran.

Cooper said last year saw the highest percentage of Iranian weapons confiscated, “three times more than the previous year.”