Namely, Reuters reports that Venezuela shipped 31 cargoes of crude and refined products last month carrying an average of 848,500 barrels per day (bpd), increasing from the 814,000 bpd the previous month.

This year, the US sanctioned two units of longtime PDVSA business partner Rosneft due to allegations of hiding the country of origin for Venezuelan crude shipments.

In fact, the US government set a May 20 deadline for the Russian energy giant to wind down purchases of Venezuelan oil and for ultimate customers to buy from Rosneft.

Those measures impacted Venezuela’s oil exports in March. Rosneft, which had been re-selling up to two-thirds of the cargoes, and other key customers such as India’s Nayara Energy and Reliance Industries reduced purchases from PDVSA.

However, others, mainly Mexico-based Libre Abordo and Schlager Business Group, replaced Rosneft as the largest intermediaries of Venezuelan crude.

Rosneft in March sold all its Venezuelan assets to an unknown company owned by the Russian government. US officials have said sanctions on Rosneft’s trading units could be lifted when it is clear they are no longer involved in Venezuela.

What is more, US Secretary of State Mike Pompeo and special envoy for Venezuela, Elliott Abrams, said the State Department, the Treasury and the U.S. Embassy in Mexico are investigating the firms as they believe they are acting as shell companies.