Yemen’s officials on wednesday reiterated their fears that a stranded oil tanker could explode and cause serious pollution off the country’s Red Sea coast.

Loaded with nearly 1.1 million barrels of oil, the tanker Safer has been stranded some 7 km off Yemen’s Ras Isa port, north of the city of Hodeidah.

In August, the United Nations attempted to assess the Safer. But the Houthis rebels blocked the access to the derelict tanker that was being used as a floating storage for oil transfers.

The Houthis placed submitting the revenues from the sale of the oil aboard the tanker to their bank in Sanaa as a precondition to allowing the UN inspection team to reach the Safer.

Officials of the Saudi-backed Yemeni government, based in the southern port city of Aden, expressed their concern that the Houthis are still refusing to grant the international inspectors access to the decaying oil tanker.

They said the tanker is at the risk of exploding as it has remained without maintenance since it fell under the control of the Iranian-backed Houthi rebels in 2015.

“The tanker is in a pressing need for urgent maintenance,” as four years’ accumulation of flammable gases and the formation of hydrocarbon gases may lead to a blast, an official told Xinhua on condition of anonymity.

He said, “For several times, the Yemeni government called for international assistance in preventing the potentially serious oil pollution threatening the Red Sea’s ecology but received no active response.”

The international community should exert more efforts in pressuring and forcing the Houthi rebels to allow the UN’s technical team to carry out necessary maintenance of the tanker and aborting any environmental disaster, the official said.

Last month, the country’s Ministry of Foreign Affairs dispatched a newly written speech to the UN Secretary-General Antonio Guterres to appeal for international assistance in preventing a potential environmental disaster due to the deterioration of the offloading terminal.

In June, UN Under-Secretary-General for Humanitarian Affairs Mark Lowcock warned the Security Council that “if the tanker ruptures or explodes, we could see the coastline polluted all along the Red Sea.”

“Depending on the time of year and water currents, the spill could reach from Bab-el-Mandeb to the Suez Canal — and potentially as far as the Strait of Hormuz,” added Lowcock, who is also the world organization’s emergency relief coordinator.

Bab-el-Mandeb is the strait between Yemen on the Arabian Peninsula and Djibouti and Eritrea in the Horn of Africa, connecting the Red Sea to the Gulf of Aden.

“If a major spill occurs, the world will surely demand answers from anyone who could have prevented the catastrophe but chose not to,” Lowcock said.

Salah Bin Laghbar, a southern political expert, told Xinhua that the Houthi rebels pay no concern about the dangerous environmental impacts but only concentrate on gaining revenues of the oil sale estimated at around 80 million U.S. dollars.

“The Houthis are besieged financially and need to finance their military campaigns against the southern regions regardless of the environmental catastrophe that may occur as a result of their obstruction to maintenance of the tanker,” said Laghbar.

The impoverished Arab country has been locked into a civil war since the Iran-backed Shiite Houthi rebels overran much of the country militarily and seized all northern provinces, including the capital Sanaa, in 2014.

Saudi Arabia leads an Arab military coalition that intervened in Yemen in 2015 to support the government of President Abd-Rabbu Mansour Hadi after Houthi rebels forced him into exile.