Yemen’s Houthi group has agreed to allow tugboats and rescue ships to reach a damaged crude oil tanker in the Red Sea, Iran’s mission to the United Nations has said, after the Iran-aligned gunmen attacked the Greek-flagged vessel last week, Reuters reports.

The Sounion tanker is carrying 150,000 tonnes, or 1 million barrels, of crude oil and poses an environmental hazard, shipping officials said. Any spill has the potential to be among the largest from a ship in recorded history.

“Several countries have reached out to ask Ansarullah (the Houthis), requesting a temporary truce for the entry of tugboats and rescue ships into the incident area,” Iran’s UN mission in New York said.

“In consideration of humanitarian and environmental concerns, Ansarullah has consented to this request,” it said.

Yemen’s Houthis spokesperson Mohammed Abdulsalam told Reuters on Wednesday there is no temporary truce and the group only agreed to allow the towing of oil tanker Sounion after several international parties contacted the group.