(Reuters) - Venezuela’s oil inventories have started to build up at the country’s ports and terminals as PDVSA is finding it cannot export crude at its usual rate due to U.S. sanctions imposed earlier this week, according to sources and shipping data.

FILE PHOTO - An oil pumpjack and a tank with the corporate logo of state oil company PDVSA are seen in an oil facility in Lagunillas, Venezuela January 29, 2019. REUTERS/Isaac Urrutia

Sanctions announced on Monday by the administration of U.S. President Donald Trump, aimed at driving President Nicolas Maduro out of power after his contested re-election last year, have barred PDVSA’s U.S. customers from transferring payments to the firm. That is effectively limiting state-owned PDVSA from shipping that oil because Maduro’s government cannot collect the proceeds.

As of Wednesday, Venezuela had 25 tankers with nearly 18 million barrels of crude - representing about two weeks of the country’s production - either waiting to load or expecting authorization to set sail. Most of those were anchored near the port of Jose, the country’s largest, according to Refinitiv Eikon data.

PDVSA responded to the U.S. sanctions by prohibiting tankers loading oil bound for the United States to leave Venezuelan ports if cargoes are not prepaid.

In addition, PDVSA’s inability to pay for crucial imports means fuel imports are delayed, adding to the glut of tankers off Venezuela’s coast.

“We are facing problems to continue storing Merey crude,” a PDVSA source said, referring to the most common crude grade it exports.

Most cargoes were bound for U.S. customers - including PDVSA’s refining unit Citgo Petroleum, Chevron Corp, Valero Energy and PBF Energy. Other large vessels loaded with Venezuelan oil and fuel were waiting to depart for Singapore, India and China.

PDVSA exported 1.25 million barrels per day (bpd) of crude last year, including 500,000 bpd to the United States. The company boosted sales in early January in anticipation of sanctions, according to the Refinitiv Eikon data.

Wills Rangel, a PDVSA board member, on Wednesday told Reuters the state-owned company, which is currently producing 1.2 million bpd of crude, does not plan to cancel supply contracts with U.S. clients. That comes even though PDVSA President Manuel Quevedo on Tuesday said a declaration of force majeure that would free PDVSA from paying penalties for undelivered cargoes was under consideration.

Meanwhile, PDVSA is eying exports to other destinations.

“An instruction was given to define new export markets in 15 to 30 days,” Rangel said.

The company is looking to India for more imports and is also considering imports of light crude if necessary to boost domestic production of gasoline.

Washington’s measures against the socialist Maduro, who has overseen the country’s economic collapse and an exodus of millions of Venezuelans in recent years, aim to back a new government formed by the opposition leader Juan Guaido.

GASOLINE IN SHORT SUPPLY

PDVSA is facing problems unloading fuel imports for domestic use because sanctions are making it difficult to complete payments for deliveries, according to Rangel, who also leads the firm’s labor union.

Sanctions require PDVSA’s U.S.-based customers, including its refining arm Citgo Petroleum, to deposit proceeds from imports of Venezuelan oil in special accounts out of Maduro’s reach.

They also limit U.S. dollar transactions with PDVSA, but do not specify if U.S. fuel can still be exported to Venezuela.

“Even being here and having secured the money, shippers in some cases have intended to block tankers from discharging,” said Rangel.

PDVSA will insist the fuel cargoes are discharged and try to find a way to pay for them, according to Rangel. He did not elaborate on how the state-run company would convince suppliers and shipping firms hired to transport the cargoes to accept payments and discharge shipments under PDVSA’s terms.

Venezuela’s main fuel providers are Citgo and India’s Reliance Industries Ltd, which typically ships naphtha, alkylate for gasoline, diesel and components from the United States, according to internal PDVSA trade documents.

PDVSA has fuel inventories at its terminals sufficient to cover a month of domestic Venezuelan consumption, according to Rangel’s numbers, as its main refining complex, the Paraguana Refining Center, is working at 40 percent of its 955,000-barrel-per-day capacity.

But sources at PDVSA estimate stocks at closer to 15 days of consumption, with little finished gasoline or diesel.

As of Wednesday, over 15 tankers were anchored near PDVSA’s ports waiting to discharge some 5.5 million barrels of imported diesel, gasoline, vacuum gasoil, liquefied petroleum gas and naphtha - enough for an estimated 13 days of consumption.

That would give PDVSA more leeway to supply gas stations and power plants if tankers are finally discharged.