The salvage operation of the oil tanker MV Sounion, which was recently attacked by Iran-aligned Houthi militants, is about to begin, the European Union's mission in the Red Sea, Aspides, said on Monday.

Aspides said in a statement that "several fires" continued to burn on the Greek-registered vessel, which is laden with about 1 million barrels of crude oil, adding that there were no visible signs of an oil spill.

The salvage operation is likely to be complex and if a spill occurs, it has the potential to be among the largest from a ship in recorded history and could cause an environmental catastrophe in an area that is particularly dangerous to access.

Explosions take place on the deck of the Greek-flagged oil tanker Sounion on the Red Sea, in this handout picture released August 29, 2024. Houthi Military Media/Handout via REUTERS

"The MV SOUNION, due to the large amount of crude oil it carries, presents a significant environmental threat. Private companies are involved in the salvage operation that is about to start," Aspides said on X.

A source familiar with the matter told Reuters that tug boats were ready to operate but it would require an on-spot inspection before a decision is made on whether to transfer the cargo to another vessel or move the ship to a safe port first.

The EU's naval force said on Monday it will provide protection to the tug boats that will deal with the salvage operation.

The Iran-aligned Houthis have been waging a campaign against commercial shipping to support Palestinians in the war between Israel and Hamas in Gaza.

On Monday, a Saudi-owned crude tanker and a Panama-flagged oil ship were attacked in the Red Sea off Yemen, two sources familiar with the matter said, although it was unclear if the vessels were hit by Yemeni Houthi militants.