The United Nations said on Friday it is encouraged that a UN team may be able to visit an oil tanker loaded with 1.1 million barrels of crude oil that is moored off the coast of Yemen, posing a serious risk to Red Sea marine life, desalination plants and shipping.

Houthi rebels, who control the area where the ship is moored, have denied UN inspectors access to the vessel.

But UN spokesman Stephane Dujarric said “the local authorities recently signaled they would approve a UN mission to the site.”