Seven oil tankers carrying an estimated 288,000 tonnes of Russian diesel are now sailing towards the United States, the first phase of a supply deal negotiated between Presidents Donald Trump and Vladimir Putin earlier this month that reverses years of sanctions on Russian oil, according to the Guardian.

The newspaper reports it is still uncertain whether the vessels will be able to unload their cargo, amid a political row over the legality of the shipments. The transport is tracked by Greenpeace, which counted seven ships while previous reports had counted three. Putin agreed to supply the US with 1.8 million tonnes of diesel in a deal announced on October 9, starting with 300,000 tonnes immediately, and Trump announced a six-month waiver of existing sanctions to allow the shipments to proceed, according to the Guardian.