The group said in a statement that it had launched ​an attack on Israel and enacted a total ban on Israeli shipping in the Red Sea, warning of further ‌escalation.

Any Houthi attacks on Red Sea shipping would worry energy markets more than three months into Iran’s closure of the Strait of Hormuz, with the war reigniting overnight.

The Red Sea, leading to the Suez Canal, is a crucial shipping lane in its own right, and during the Iran war has become the main alternative outlet for ​millions of barrels per day of Middle East oil sent by pipeline, bypassing the Gulf.

The Houthis disrupted shipping in 2023 ​to 2025 out of what they said was solidarity with the Palestinians, but had so far largely stayed ⁠out of the wider Middle East war that began with U.S.-Israeli attacks on Iran in February this year.

A Houthi source told Reuters ​that preventing Israeli ships from transiting the Red Sea was a first step, and that further escalation could lead it to stop the passage ​of any ships bound for Israel as well as other measures.

The announcement did not amount to a ban on all commercial shipping in the Red Sea and was instead “directed at vessels assessed by the Houthis as Israeli-affiliated”, British maritime risk management group Vanguard said on Monday in a note.

“Given the broad wording used, ​vessels operating in the region should maintain heightened vigilance and conduct enhanced affiliation screening.”

Shipping sources said the action could cause a wider impact because ​the Houthis have targeted ships in the past with no direct link with Israel.

“The announcement… will cause every ship to think carefully about the wisdom ‌of making ⁠a transit,” one source said. “The Houthis don’t have a good record of determining which ships have ‘links’ to Israel, so it’s probably better to go around Africa, pay the fuel bill, and benefit from lower war risk insurance costs.”

Red Sea war risk insurance rates were unchanged on Monday at around 0.3% of the value of a ship, with little movement in recent weeks, an insurance industry source said. The rates are reviewed every 24 hours, so levels could change rapidly, the source added.

Houthi attacks on Red Sea shipping during the two-year Gaza war that began in October 2023 led major companies, including Maersk and Hapag-Lloyd, to divert around Africa - a far longer, more expensive route. During that ​period, Houthi attacks on what the group called Israeli-linked vessels were expanded to include any shipping companies that ​used Israeli ports.

Shipping ⁠traffic through the southern Red Sea and the critical Bab al-Mandab strait has still not returned to pre-October 2023 levels. Average monthly sailings in March 2026 reached 1,034 crossings, compared with over 2,000 in September 2023, according to analysis from Lloyd’s List Intelligence.

The impact of any sustained threat to Red ⁠Sea shipping ​could be bigger now, however, given the closure of the Strait of Hormuz.

Most Gulf energy ​production has been unable to leave the region since the war began on February 28. However, significant volumes of Saudi crude have been transported by pipeline to its ​Red Sea export terminal at Yanbu.