United Nations, Aug 13 (IANS): Permission was being delayed for a UN team to board a derelict tanker off the coast of Yemen, which threatens to leak more than 1 million barrels of oil, a spokesman said.

"The Ansar Allah (Houthi) authorities have recently come back to us with a range of technical follow-up questions, which we have answered," Xinhua news agency quoted Stephane Dujarric, spokesman for UN Secretary-General Antonio Guterres, as saying on Wednesday.

"We hope that the authorities will authorize the mission right away."

The tanker called Safer has not been maintained for five years, UN Environment Programme Executive Director Inger Andersen told the UN Security Council last month and warned that if there is a spill, it will directly affect millions of people in Yemen and destroy entire ecosystems for decades.

Dujarric cited recent ecological disasters in Lebanon and Mauritius as reasons for early approval: the thousands of tons of ammonium nitrate left unsafe for years in a Beirut warehouse before exploding August 4, devastating the port; and the Japanese bulk carrier grounded for weeks on the Mauritius coast now leaking oil.

"That risk cannot be overstated," the spokesman told a virtual press briefing.

"We are happy to provide, and have been providing, any technical information required, and we want to keep working with everyone to get this done as quickly as possible."

He said the rebels in control of the area first indicated on July 5 that they would allow an inspection and emergency repair team to board the floating oil storage and offloading vessel.

An official UN request was sent on July 14.

Since then the Houthis have requested additional information on the team and its operations, said the spokesman.