Oil-tanker tracking companies say the tankers carrying oil and petroleum products from Saudi Arabia have changed course as threats from the Houthi forces supported by the Islamic Republic have increased.

The maritime intelligence company Windward says five tankers carrying 3.84 million barrels of crude oil, diesel and naphtha originating in Saudi Arabia reversed their routes before reaching the Bab al-Mandeb Strait.

The Financial Times also reported yesterday, citing shipping data, on the rerouting of four tankers linked to Saudi Arabia, and wrote, quoting two sources, that Yemen’s Houthis have warned ships in the area via radio messages that if they have docked at Saudi ports, they will not be allowed to pass through the Bab al-Mandeb Strait—between the Red Sea and the Gulf of Aden.

According to estimates by the company Kepler, since the Islamic Republic blocked the Strait of Hormuz, Saudi Arabia has exported nearly 4.9 million barrels of crude oil per day from the port of Yanbu and via the Red Sea route since April.