- Gateway to Red Sea -

Known as the "Gate of Tears" in Arabic, the Strait of Bab al-Mandeb is a narrow waterway at the southern tip of the Red Sea, connecting it with the Gulf of Aden in the Indian Ocean.

About 100 kilometres (62 miles) long and 30 kilometres (18 miles) wide, it separates Yemen on the Arabian Peninsula from Djibouti and Eritrea on the Horn of Africa.

- Strategic trade route -

With the Red Sea acting as a key link between Europe and Asia, the strait is one of the busiest shipping lanes in the world.

Oil tankers and cargo ships arriving from the Indian Ocean pass through it to reach the Red Sea and then the Suez Canal, where they enter the Mediterranean, and vice versa.

Around 26,000 ships transited through the Suez Canal in 2023, according to a Suez Canal Authority report -- but this fell to 12,700 by 2025 after Huthi rebels attacked ships in the Red Sea.

- Key oil passage -

The US Energy Information Administration (EIA) said 12 percent of world oil shipments passed through Bab al-Mandeb in the first half of 2023, before the Huthi attacks later that year.

Data published by the EIA indicates that the volume of oil transiting through Bab al-Mandeb in the first half of 2025 was less than half of the total volumes in 2023.

With Iranian forces closing off access to the Gulf via the Strait of Hormuz, exports via the Saudi Red Sea port of Yanbu meanwhile have approximately tripled to a record high of around four million barrels a day, according to analysts, including research group Rystad Energy.

- Militarised zone -

The region is one of the most highly militarised zones in the world.

The United States and France have major military bases in Djibouti and China in 2017 also opened its first such overseas base there.

After the conflict between Israel and Hamas militants erupted in Gaza in October 2023, the Huthis threatened to attack any ship heading to Israeli ports and stepped up their raids.

In response the European Union in 2024 launched a naval operation dubbed Aspides to protect shipping in the Red Sea.

US and UK forces also carried out strikes on Huthi targets in response to their attacks.

- Iranian threat -

The latest Middle East war erupted on February 28 when the United States and Israel began bombing Iran, prompting Tehran to retaliate with strikes across the region.

Iran's threat to Hormuz has driven up tanker traffic slightly through Bab al-Mandeb, said Rico Luman, a transport economist at ING bank.

"We're talking about three to four tankers more per day, which is still a notable difference," he told AFP.

Iranian news agency Tasnim on Wednesday quoted an unnamed military official as saying that Iran would target shipping in the Red Sea if the United States "attempts a ground operation... or if it seeks to impose costs on Iran through naval manoeuvres" in the Gulf region.

"The Bab el-Mandeb Strait is among the most strategic straits in the world, and Iran has both the will and the capability to pose a fully credible threat against it," the official said.