The United Arab Emirates banned arriving ships that carry the flag of landlocked African nation Eswatini, the latest sign of the Middle East nation distancing itself from risky vessels that help haul Russian oil supplies.

The Eswatini flag is now on a list that restricts calls to UAE ports and waters, according to a government circular posted on the Port of Fujairah website. The flag of Cameroon was listed earlier this year.

Vessels sailing under both flags have transported oil for Moscow after it assembled a shadow fleet of ships to help keep sanctioned supplies moving. The ban won’t apply to ships assessed by a wider international classification body.

Flag states are key to maintaining safety standards in global shipping. For oil tankers, Liberia and the Marshall Islands are among the largest providers, but after the invasion of Ukraine a series of less well-known flags emerged, with questions about the strength of their safety standards.

Eswatini — formerly Swaziland — is a particularly new player, with no ships sailing under its flag in 2023, according to Clarkson Research Services Ltd., a unit of the world’s largest ship broker. That number is now at 26 ships, though not all of them would be tankers.

Of 18 Eswatini-flagged ships visible in ship-tracking data compiled by Bloomberg, the ownership of 16 is unclear. Several tankers in that list have hauled oil produced in Russia and Iran, according to Kpler data.