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 said on Wednesday, after the Iran-aligned militants attacked the Greek-flagged vessel last week.

The Sounion tanker is carrying 150,000 metric tons, 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.