The amount of oil being stored at sea globally climbed to the highest in more than two-and-a-half years, aided by an unusual stash of Saudi Arabian barrels in the Red Sea.

About 129 million barrels of crude were sat stationary on oil tankers in the week to June 23, according to data from Vortexa, an analytics firm. That’s the most since October 2020. Storage volumes in Asia hit an 11-month high last week, while those in the Middle East were the highest since January.

A cluster of Saudi oil tankers has built up in the Red Sea, though there have been tentative signs in recent days that the number of vessels might be starting to dwindle. In recent months, some ports in China have also begun stepping up checks on older vessels, keeping some cargoes waiting.

While floating storage has been increasing in recent weeks, the total volume of oil at sea — which includes barrels in transit — is actually falling. That’s because oil being transported has declined. OPEC+ has reduced its crude production in recent months, while Saudi Arabia has said it will further cut output from the start of July.