The U.S. said on Wednesday it had seized 90 separate shipments of biodiesel bound for Cuba worth nearly US$3 million, the second time in a week U.S. authorities have announced the seizure of “illegal” fuel en route to the island nation. The enforcement action comes as the Trump administration continues to strangle Cuba’s energy sector, allowing only relatively small shipments of fuel to reach the island’s private sector in a program aimed at undercutting the Cuban government. The U.S. Department of Homeland Security Miami Special Agent in Charge Jose Figueroa told reporters in Miami on Wednesday that the seized shipments were bound for Enetec, a Havana-based, state-owned fuel company sanctioned by the U.S. earlier this year. Authorities said they had intercepted the fuel shipments in Houston and at Port Everglades, in south Florida, before they departed the U.S. More than 600,000 gallons of fuel were seized, Homeland Security said. “An effort of this magnitude to undermine U.S. sanctions does not occur by accident,” Figueroa said. “These actions concern shipments suspected of benefiting the Cuban regime through a state-controlled entity. “Those who seek to undermine U.S. law to finance, facilitate or benefit from such efforts should be on notice.” Cuba`s government did not immediately comment on the fuel seizure. The Trump administration’s fuel blockade on Cuba has been called “illegal” by the United Nations and “economic warfare” by Cuba`s communist-run government. It has vastly worsened ongoing blackouts, water shortages and inflation across the island, pushing the island toward a humanitarian crisis. U.S. President Donald Trump has openly stated that his goal with the blockade and sanctions is to upend Cuba’s government. The U.S. coast guard late last week announced that it had intercepted a large container ship in September carrying fuel bound for Cuba. It said the ship had attempted to evade authorities and that it carried large quantities of fuel hidden in its ballast tanks. The U.S. has not revealed the identity of the exporters in either case. Reporting by Dave Sherwood, Editing by Nick Zieminski