At least seven oil tankers have made sharp U-turns close to Yemen since the Iran-linked Houthi group announced a “maritime embargo” against Saudi Arabia on Monday, ship-tracking data shows. All of the ships were travelling either to or from Saudi ports and altered course after the embargo was declared.

Red Sea Trade Disruption and Global Implications

Nearly 15% of global sea trade moves through the Red Sea, a critical route connecting the Mediterranean and Gulf of Aden via the Suez Canal in Egypt and the Bab al-Mandab Strait between Yemen and the Horn of Africa. The Red Sea has become a key export route for Saudi oil since the US-Israeli war with Iran led to the closure of the Strait of Hormuz, severely restricting Gulf oil and gas flows.

Rosemary Kelanic from the US-based Defense Priorities think tank noted the embargo’s potential impact; “This has played a major role in relieving pressure to global markets,” she said. “If the Houthis further restrict trade, prices will go up.”

According to maritime intelligence firm Kpler, 20 vessels entered the Red Sea and 22 exited via the Bab al-Mandeb strait the day before the Houthi blockade was announced. Kelanic added that any Houthi attacks on vessels in the Red Sea or Gulf of Aden “will suppress all international traffic, not just Saudi-bound vessels.”

EU Advises Vessel Avoidance Amid Rising Tensions

The EU’s naval force in the region, Aspides, recommended on Wednesday that “merchant vessels linked to Israeli, US or Saudi interests avoid transiting the Red Sea and Gulf of Aden until the threat level decreases,” according to an advisory seen by Reuters news agency.

Ship-tracking data from MarineTraffic reveals the crude oil tanker Rodos, loaded with Saudi crude, departed for India from the Red Sea port of al-Muajiz on Monday evening. The Liberian-flagged ship initially set off south toward the Bab al-Mandab Strait but made a U-turn about nine hours later and began sailing north instead.

Another Liberian-flagged oil and chemical tanker, Mica, departed Saudi Arabia’s Jazan port on Monday afternoon and also reversed course — Ship-tracking data also indicates at least eight ships bound for the Red Sea made U-turns instead of entering the Bab al-Mandab Strait from the south.

The Marshall Islands-flagged vehicle carrier Liu Jiang Kou was sailing to Saudi Arabia’s Jeddah port from China when it changed course entirely on Monday in the Gulf of Aden. A Hong Kong-flagged crude oil tanker. New Prime. Also turned around as it headed toward Saudi Arabia and is now waiting in the Arabian Sea.

While the reasons for each course change cannot be independently verified, “the timing is consistent with the embargo announcement,” said maritime risk management company Vanguard.

Yemeni Civil War and Regional Tensions

In an email to shipowners seen by the BBC, the Houthis stated “vessels are banned from loading or discharging cargo at any Saudi ports.” They also warned that ships “may be subject to targeting in any location within the operational reach.” The Houthis claimed their embargo is in response to a Saudi blockade of ports and airports in Houthi-controlled north-western Yemen.

Saudi Arabia has denied the allegations and vowed to “take all necessary measures to protect its ships in accordance with international law.” The conflict in Yemen began in 2014 when the Houthis captured the capital, Sana’a, from the government. The conflict escalated in 2015 when a Saudi-led coalition of Arab states intervened to restore the official government.

Since 2022, an informal truce has existed between the Houthis and Saudi Arabia. However, last week, the Houthis launched missiles at an airport in south-western Saudi Arabia in response to air strikes on Sanaa’s airport they blamed on the kingdom.

The Houthis have previously disrupted the Bab al-Mandab Strait, a vital waterway. Shortly after the Gaza war began in October 2023, the Houthis began attacking merchant vessels in the Red Sea and Gulf of Aden, claiming they were supporting Palestinians. These attacks resulted in four ships being sunk, one vessel seized, and nine crew members killed.

With the Strait of Hormuz closed. Saudi Arabia has diverted more than 70% of its crude exports from the Gulf to the Red Sea port of Yanbu through an east-west pipeline. Recent data from Kpler and Signal Ocean indicates about four million barrels per day have been shipped from Yanbu in recent weeks, compared with around 973,000 a year earlier.

“The only option left to the Saudis if the Bab al-Mandab Strait is effectively closed would be to move oil all the way through the Mediterranean and around the southern tip of Africa to get to Asia,” said Naveen Das, a senior oil analyst from Kpler. He added that while the impact of the blockade on consumers won’t be immediate, the conflict with Iran has made the global energy system more vulnerable. “We could weather it for two weeks, three weeks, even a month, but even in that time, we will see higher freight rates, higher energy prices, and that bleeds into higher energy consumer costs.”

Ships near the Red Sea are also broadcasting messages to deter attacks, a common practice since the Houthis targeted vessels during the Gaza war — At least 50 vessels in the region are broadcasting they have armed guards on board, according to data from MarineTraffic.

Martin Kelly from crisis management firm EOS Risk Group told BBC Verify that captains fear the Houthis might misinterpret their situation. “They might read your situation wrong and think your ship has called at a Saudi port in the past, then therefore you could be attacked,” he said. He added that the potential damage from an attack on large crude oil carriers would be catastrophic, with likely deaths onboard.