The United Nations announced on Friday successfully transferring all the oil carried by a decaying tanker off the Yemeni coast, ending a threat earlier described as a "ticking time bomb."

UN Secretary-General Antonio Guterres "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," a statement said.

What do we know about the vessel?

The 47-year-old tanker, called the FSO Safer, is a floating storage and offloading facility that has been moored around 50 kilometers (30 miles) from the Yemeni port of Hodeida since the 1980s. The corroding vessel has not been serviced since 2015, due to the war in Yemen.

It was carrying 1.1 million barrels of oil, four times as much as was spilled in the 1989 Exxon Valdez disaster off Alaska, according to UN officials.

On July 25, the UN began pumping oil from the decaying supertanker, in a bid to prevent an environmental disaster that it estimated would cost $20 billion (€18 billion) to clean up.

What happens next?

UN Development Program head Achim Steiner welcomed the conclusion of the UN operation.

"That removes the imminent and immediate threat that had become the focus of attention across the whole world: a tanker that could break apart or explode in the Red Sea," Steiner told the French AFP news agency.

However, the UN had earlier stipulated that emptying the aging tanker of oil was only the first step. The next phase of the project involves stripping and cleaning the Safer's tanks and readying the vessel for towing and scrapping.

Otherwise, the tanker "will pose a residual environmental threat, holding viscous oil residue and remaining at risk of breaking apart," the UN had earlier warned.

Steiner told AFP the second phase could take "anywhere between two to three weeks."

The waters where the Safer is positioned are controlled by Houthi rebels, who are involved in a conflict since 2014 with a Saudi-led coalition that backs the internationally recognized Yemeni government based in the southern city of Aden.

rmt/rc (AFP, AP, Reuters)