Technical vessels are seen by the decrepit "Safer" tanker on June 12, 2023, off the coast of Yemen. (PHOTO / AP)

ADEN, Yemen- The high-stakes oil transfer from a decaying tanker off the coast of war-torn Yemen has been safely concluded, the United Nations announced Friday, avoiding what the global body warned could have been a devastating environmental catastrophe.

UN Deputy Spokesman Farhan Haq said UN chief Antonio Guterres thanked the Yemeni authorities for their support and expressed his gratitude to the many countries, companies and individuals who contributed funds to avert disaster

UN Deputy Spokesman Farhan Haq said in a statement that the two-week-long ship-to-ship operation to pump more than 1 million barrels of crude oil from the dilapidated FSO Safer tanker to a temporary storage vessel was finished successfully on Friday.

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"The Secretary-General welcomes the news that the ship-to-ship transfer of oil from the FSO Safer to the Yemen replacement vessel has been safely concluded today, avoiding what could have been a monumental environmental and humanitarian catastrophe," the statement said.

Haq said the UN chief thanked the Yemeni authorities for their support and expressed his gratitude to the many countries, companies and individuals who contributed funds to avert disaster.

A photo shows the deck of the UN-owned Nautica vessel, moored off the coast of Yemen's contested western port of Hodeida on July 17, 2023. (PHOTO / AFP)

But he noted additional funding is still needed to remove the empty Safer tanker and eliminate any remaining environmental threats.

The FSO Safer, marooned off the port of Hodeidah since 2015, had been a ticking time bomb containing approximately 1.1 million barrels of oil. As the vessel's condition continued to deteriorate, concerns escalated regarding the potential for a devastating oil spill, which the UN warned could surpass the 1989 Exxon Valdez disaster in scale.

The ship-to-ship transfer from the decaying FSO Safer to a replacement tanker, the Yemen, began on July 25, 2023.