The UN said it is doing everything possible to get the Houthis to allow experts access to a decaying oil tanker off Yemen’s coast.

Stephane Dujarric, spokesman for the UN Secretary-General Antonio Guterres, was speaking after the militia’s leader, Mohammed Ali Al-Houthi, said the world body would be “fully responsible” if there was a major oil leak from the vessel.

Al-Houthi made the accusation despite his group repeatedly refusing access to the FSO Safer tanker, which has been described as a ticking time bomb.

Dujarric said that while discussions with the group continue, it was “not useful to negotiate these things via public statements.”

“We are eager, which is probably the understatement of the year, to get people on board the tanker,” he said. “We will do whatever is possible and we will continue to explore every avenue to make that happen as soon as possible in our discussions with the Houthi Ansar Allah people we are speaking to.”

The Safer tanker fell into Houthi hands when they took control of Hodeidah, a city on the Red Sea coast, in 2015. Its structural condition has deteriorated over the years and threatens a catastrophic leak that the UN warns could spill four times as much oil as the 1989 Exxon Valdez oil disaster.

In a tweet, Al-Houthi said: “The UN says there is a high risk of the Safer leaking and (causing) an environmental disaster, so we said, come with your experts to fix it.”

He added: “Months and days went by without a response. We reiterate that the United Nations will be held fully responsible for any leakage.”

His comments would have irritated UN negotiators after the Houthis have repeatedly prevented any neutral party from accessing the ship.

The dilapidated tanker is carrying around 1.14 million barrels of oil and if it breaks up would spark a catastrophic environmental and humanitarian disaster in the Red Sea.

Last week, the Yemeni government repeated warnings to the international community of the catastrophic risks of a leak, sinking, or explosion of the Safer tanker.

“The Houthis are using the FSO Safer as a time bomb and a means to blackmail and pressure the international community for political and material gains. Unfortunately, the Houthis are not interested in the looming environmental, economic and humanitarian disaster,” Information Minister Moammar Al-Eryani told Arab News.

He called on the international community to urge the Houthis to allow a technical team to assess the status of the tanker.

The UN previously said it had not been able to resolve maintaining the tanker with the Houthi militia for two years.