The International Maritime Organization reported a widespread oil leak from the grounded tanker “Caroline Bzangi” and said that the oil slick has now reached the shores of mainland Oman.

A spokesperson for the international body said the oil is moving in coastal waters toward the northeast of the Al-Qabliyah island in Oman, and that oil spill response plans are underway.

The government of Oman had announced on Monday that the oil slick formed near a protected natural area in the country had covered an area of nearly 400 square kilometers.

The tanker, which was carrying about 800,000 barrels of Russian oil for transfer to Asia, ran aground near the coast of Oman on June 30 and is now about 22 nautical miles away from the Omani fishing village of Sharbatat.