MEXICO CITY/MUMBAI (Reuters) - Indian refiner Reliance Industries Ltd RELI.NS is scheduled to resume loading Venezuelan crude in October after a four-month pause, according to sources and internal documents from PDVSA seen by Reuters, a move that could help Venezuela's state-run company drain its large oil inventories.

FILE PHOTO: The logo of Reliance Industries is pictured in a stall at the Vibrant Gujarat Global Trade Show at Gandhinagar, India, January 17, 2019. REUTERS/Amit Dave

The United States in January imposed the toughest sanctions yet on Venezuela’s oil industry, depriving the OPEC member of the main destination for its crude exports.

In August, Washington added to the sanctions pressure by threatening non-U.S. companies with punitive action if they “materially assist” Venezuelan President Nicolas Maduro’s government.

The measures have scared away several of PDVSA’s largest customers and tanker operators, causing a fast accumulation of unsold crude that forced the Venezuelan company last month to reduce output.

A Reliance representative said on Wednesday it has been supplying Venezuela with fuels permitted under U.S. sanctions, including diesel, and thus it “is able to recommence crude sourcing” in exchange for the refined products.

“These are actions compliant to U.S. sanctions as crude sourcing against supply of permitted products is allowed,” the representative said in a email to Reuters.

PDVSA did not reply to a request for comment.

China National Petroleum Corp and its units stopped taking Venezuelan oil in August. Others, including Reliance, have recently been buying Venezuelan crude from Russian major Rosneft ROSN.MM, according to the documents and vessel tracking information from Refinitiv Eikon.

Reliance and the state-run Russian oil company did not respond to requests for comment on these trades.

Reliance needs the type of heavy sour crude that Venezuela sells because its refineries are configured to process it. U.S. sanctions on both Venezuela and Iran have made it harder for the refiners to find supplies of these crude grades.

The Indian firm is sending at least two vessels, the very large crude carriers Antonis I. Angelicoussis and Maran Castor, to Venezuela’s Jose port for loading in late October, according to the PDVSA documents.

The tankers are currently passing the Suez canal, the Refinitiv Eikon data showed.

According to the same PDVSA documents, Italy's Eni ENI.MI has separately sent the Suezmax tanker Seavoyager to load 1 million barrels of Venezuelan Merey heavy crude in mid-October.

Asked about the shipment, an Eni spokesman said the last time the Italian firm received crude from PDVSA was in late 2018. He did not comment on the cargo allegedly scheduled for October.

“Eni confirms that it has been recovering its receivables with PDVSA through crude supplies, in full compliance with all relevant regulations,” the company told Reuters in an email.

The scheduled exports come at a time when PDVSA desperately needs to draw down almost 39 million barrels of unsold oil stocks that have forced it to reduce output and suspend crude blending while shipping more barrels to its political ally Cuba.

A source from one of PDVSA’s joint-venture projects said it was shipping to Cuba and other cargoes would go to Reliance. “We need to make room for storage, otherwise we would have to stop output,” the source said.

Besides Rosneft, which takes PDVSA's oil as repayment of billion of dollars lent to Venezuela in the last decade, Spain's Repsol REP.MC has since 2018 taken PDVSA's crude oil in lieu of dividend payments and also supplying Venezuela with fuel.

Rosneft is scheduled to take at least 7.9 million barrels of Venezuelan oil this month, equivalent to 255,000 barrels per day (bpd), according to the PDVSA document. Venezuela produced between 600,000 and 700,000 bpd of oil last month, according to independent estimates.

The Russian firm became PDVSA’s largest customer in July.

The U.S. Treasury has made clear that transactions between U.S. firms and PDVSA, controlled by Maduro’s government, are not allowed under sanctions but some officials have said oil shipments delivered to foreign firms to repay debt are allowed as long as they do not involve cash payments.