More than 10 tankers loaded with Venezuelan crude and fuel have left Venezuelan waters in “dark mode” in recent days, after previously turning off their monitoring systems (AIS transponders), apparently violating a strict blockade imposed by the United States amid intense pressure that has been growing until the capture of President Nicolas Maduro, monitoring service TankerTrackers.com said, quoted by Reuters on Monday.

All of the identified ships that left Venezuelan waters are under US sanctions. A separate group of ships, also under sanctions, left the country in recent days, empty, after unloading imported products or completing domestic transport runs, according to Agerpres.

The departure of these ships provides a breath of fresh air for Venezuelan state company PDVSA, which had accumulated huge stocks as exports were almost completely blocked in recent weeks due to the US blockade.

Oil exports are Venezuela’s main source of income. An interim government, now led by Oil Minister and Vice President Delcy Rodriguez, will need the revenue to finance spending and ensure the country’s internal stability, Reuters notes.

At least four of the tankers left Venezuelan waters via a route north of Margarita Island, after making a brief stop near the country’s maritime border, TankerTrackers.com reported, after identifying the ships in satellite imagery.

A source familiar with the departures documents told Reuters that at least four supertankers had been authorized by Venezuelan authorities in recent days to leave Venezuelan waters in “dark mode,” making them invisible on commercial tracking radars.

It was not immediately clear whether the departures were in defiance of U.S. measures. US President Donald Trump said on Saturday that an “oil embargo” on Venezuela was in place, but added that under a future transition, Venezuela’s biggest customers, including China, would continue to receive oil.