Yemen's Houthi forces have warned of renewed attacks on Red Sea shipping as US-Iran tensions escalate, casting doubt on carriers' plans to resume services via the shorter Suez Canal route, reports London's S&P Global.

A video posted by the Houthis showed a ship on fire with the caption "Soon," followed by a statement from spokesman Brigadier Yahya Saree warning of retaliation against the US and Israel if Washington strikes Iran. The group had paused attacks in November after the Israel-Hamas ceasefire but now threatens to resume operations.

Iran's crackdown on anti-government protests in December prompted US President Donald Trump to threaten military action, with a carrier strike group led by the USS Abraham Lincoln heading to the region. The developments have heightened concerns over shipping security.

Even before the latest threat, CMA CGM said it would scale back plans to send three Asia-Europe services through the Suez, citing the uncertain international context. Maersk, meanwhile, is due to reroute its MECL service from India to the US East Coast via the Suez, but included a caveat in its advisory that contingency plans could revert sailings to the Cape of Good Hope.

Most major carriers continue to use the longer route around southern Africa, which has absorbed about eight per cent of global capacity since Houthi attacks began in late 2023. Analysts say this has helped prevent freight rates from falling.

DHL Global Forwarding's Bjoern Schoon said a full-scale return to the Red Sea would initially risk congestion and higher costs, but once stabilised, shippers would benefit from faster transit times and more competitive pricing.