India, Jan. 6 -- CARACAS/HOUSTON, January 6 - At least a dozen oil tankers loaded with 12 million barrels of Venezuelan crude have sailed from the country since January 1, apparently defying a U.S. naval blockade, according to shipping data and documents. The departures come as U.S. oil major Chevron separately resumed authorized exports to the United States, highlighting a fractured enforcement landscape days after President Nicolas Maduro's capture.

The vessels, all under U.S. sanctions, had been stuck in Venezuelan waters since President Donald Trump imposed a quarantine on sanctioned tankers in mid-December. Shipping monitors and internal documents show at least four supertankers were cleared by Venezuelan authorities to sail in "dar...