TEHRAN, Iran -- Iran said Friday two missiles struck one of its oil tankers travelling through the Red Sea off the coast of Saudi Arabia, a mysterious assault not immediately corroborated that still spiked oil prices amid months of heightened tensions at sea across the wider Mideast.

There was no acknowledgement of the incident from Saudi Arabia, which in September had more than half of its daily crude oil production knocked out by an assault the U.S. blamed on Iran, something denied by Tehran.

All the attacks came after President Donald Trump's decision to unilaterally withdraw America from Tehran's nuclear deal with world powers and impose crushing sanctions targeting Iran's crude oil sales and shipments. Iranian officials warned for weeks that if they couldn't sell their oil, neither would anyone else in the region.

"This latest incident, if confirmed to be an act of aggression, is highly likely to be part of the wider narrative of deteriorating relations between Saudi and the U.S. and Iran," private maritime security firm Dryad Maritime warned.

"It is likely that the region ... will face another period of increasing maritime threats, as the Iranian and Saudi geopolitical stand-off continues," it added.

U.S. Defence Secretary Mark Esper said the U.S. will send fighter jets and additional air defences to the Saudis to help defend the kingdom against Iran amid the heightened tensions. He called Saudi Arabia a longstanding security partner in the region.

The attack reportedly took place around 5 a.m. and damaged two storerooms aboard the oil tanker Sabiti, state media reported. It also briefly caused an oil leak into the Red Sea near the Saudi port city of Jiddah that later was stopped, state-run IRNA news agency reported.

The Sabiti turned on its tracking devices late Friday morning in the Red Sea, putting its location some 130 kilometres (80 miles) southwest of Jiddah, according to data from MarineTraffic.com. The ship is carrying some 1 million barrels of crude oil, according to an analysis from data firm Refinitiv.

The Sabiti last turned on its tracking devices in August near the Iranian port city of Bandar Abbas. Iranian tankers routinely turn off their trackers as U.S. sanctions target the sale of Iran's crude oil.

Images released by Iran's Petroleum Ministry appeared to show no damage to the Sabiti visible from its bridge, though they did not show the ship's sides. Satellite images of the area showed no visible smoke.

The ministry's SHANA news agency said no ship nor any authority in the area responded to its distress messages.

Foreign Ministry spokesman Abbas Mousavi described the incident Friday as an "attack" carried out by those committing "dangerous adventurism." In a statement, Mousavi said the Sabiti was struck twice in the span of a half hour and an investigation was underway.

Iranian authorities did not say who they suspected of launching the missiles, suggesting officials were waiting to assess the incident while waiting for a visit by Pakistani Prime Minister Imran Khan on Saturday.

Khan met Iranian President Hassan Rouhani in September on the sidelines of the U.N. General Assembly. He also met him on an April visit to Tehran. Khan has been seeking to serve as a go-between for Iran and Saudi Arabia.

Lt. Pete Pagano, a spokesman for the U.S. Navy's 5th Fleet overseeing the Mideast, said authorities there were "aware of reports of this incident," but declined to comment further.

Benchmark Brent crude oil spiked over 2% in trading Friday before dropping back down under $60 a barrel.

Since May, there have been a series of oil tanker attacks near the Strait of Hormuz, the mouth of the Persian Gulf through which 20% of all oil passes. While Tehran denies being involved, the U.S. Navy says Iran used magnetic mines on the vessels. The Navy released video it said showed Iranian Revolutionary Guard members taking an unexploded mine off one vessel, an incident still not explained by Tehran.

Iran meanwhile has shot down a U.S. military surveillance drone and seized several oil tankers amid the heightened tensions.

The latest assault saw Saudi Arabia's vital oil industry come under a drone-and-cruise-missile attack , halving the kingdom's output. The U.S. has blamed Iran for the attack, something denied by Tehran. Yemen's Houthi rebels, whom the kingdom is fighting in a yearslong war, claimed that assault, though analysts say the missiles used in the attack wouldn't have the range to reach the sites from Yemen.

Friday's incident also renewed questions about safety in the Red Sea, another crucial shipping route. Mousavi said that Iranian tankers have been targeted by "damaging activities" over recent months in the Red Sea. He did not elaborate.

In May, an Iranian oil tanker carrying more than 1 million barrels of fuel oil suffered a reported malfunction in the same area as the Sabiti came under attack. The kingdom helped the Happiness 1 reach anchorage off Jiddah, where it was repaired and later left.

In its analysis Friday, Dryad Maritime said the incident involving the Happiness 1 bore "the hallmarks of a potential explosive incident."

Iran said in August another oil tanker, the Helm, faced a technical failure while passing through the Red Sea, without elaborating.

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Gambrell reported from Dubai, United Arab Emirates.

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Associated Press writer Lolita C. Baldor in Washington contributed

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Gambrell reported from Dubai, United Arab Emirates.