MATANZAS, Cuba, Jan 8 (Reuters) - Cubans braced for a deepening economic crisis after the United States seized two more Venezuela-linked oil tankers on Wednesday, a move that threatens to sever a critical energy lifeline for the Communist-run island just days after U.S. forces captured Venezuelan President Nicolas Maduro.

In the port of Matanzas where oil tankers dock, shuttered gas stations and long fuel lines reflected mounting supply shortages. The latest U.S. action is stoking fears that already-frequent, hours-long power cuts will worsen.

"Now I think that with this situation, things will get worse, because now they won't let oil come," William Gonzalez, a Matanzas resident, told Reuters. "Before oil came from Venezuela and Russia, now it will only come from Russia...So that's one less source of oil, so the country must get a little worse."

In a dramatic escalation of its pressure campaign, the U.S. military on Wednesday seized the Russian-flagged tanker 'Marinera' in the Atlantic near Iceland after a two-week pursuit, U.S. officials said.

The seizure, which a senior Russian lawmaker decried as "outright piracy," marks the fourth such interception since Washington imposed a blockade on all sanctioned vessels going in and out of Venezuelan waters in mid-December.

Earlier on Wednesday, the U.S. Coast Guard had intercepted another Venezuela-linked tanker, the 'M Sophia,' northeast of South America.

For Cuba, the loss of Venezuelan oil is devastating. Between January and November of last year, Venezuela sent an average of 27,000 barrels per day (bpd) to the island, covering roughly 50% of Cuba's oil deficit, according to shipping data and documents from Venezuelan state oil company PDVSA.

"The repercussions are not going to be very good. Venezuela was one of the countries that helped us the most with energy and fuel," said Mario Valverde, a business owner in Havana.

While Mexico has become an "important supplier," President Claudia Sheinbaum said on Wednesday that Mexico is not sending more oil to Cuba than it has historically.

The aggressive U.S. posture has been met with a mix of anger and grim determination by some Cubans.

"We are very dissatisfied with (U.S. President Donald) Trump's attitude toward Maduro, because that is forcing a country to submit by force," said resident Manuel Rodriguez. "If there are more blackouts, we will have to endure the blackouts as Cubans and resist until the end."

(Reporting by Reuters TV; Writing by Kylie Madry; editing by Diane Craft)