Yemen’s Houthi rebels have released footage showing that they boarded and intentionally set explosives aboard a Greek-flagged tanker that had been abandoned after they repeatedly attacked it.

The incident put the Red Sea at risk of a major oil spill.

The Houthis chanted their group’s motto as the explosives detonated aboard the oil tanker Sounion: “God is the greatest; death to America; death to Israel; curse the Jews; victory to Islam.”

The Sounion carried some one million barrels of oil when the Houthis initially attacked it last week.

In the time since, Western countries and the UN have warned any oil spill from the Sounion could devastate the coral reefs and wildlife that call the Red Sea home.

The Houthis have been attacking shipping over the Israel-Hamas war for months now and say they will continue those attacks.

They suggested that they may allow the Sounion to be salvaged, although the rebels already once blocked crews trying to reach the abandoned vessel, the US military said.