The first of five Iranian tankers carrying fuel for petrol-starved Venezuela entered the South American country's exclusive economic zone late on Saturday, despite a US official's warning that Washington was considering a response to the shipment.
The tanker, named Fortune, reached the country's waters at about 7.40pm local time after passing north of the neighboring dual-island Caribbean nation of Trinidad and Tobago, according to vessel-tracking information from data-analysis company Refinitiv Eikon.
"The ships from the fraternal Islamic Republic of Iran are now in our exclusive economic zone," tweeted Tareck El Aissami, Venezuela's recently appointed oil minister.
Venezuelan state television showed images of a naval ship and aircraft preparing to meet it. The country's defense minister had pledged that the military would escort the tankers once they reached Venezuela's waters due to what the authorities described as threats from the US.
The tanker flotilla is carrying 1.53 million barrels of petrol and alkylate to Venezuela, according to both governments and calculations by TankerTrackers.com.
The desperately needed shipments have caused a diplomatic standoff between the US and Iran and Venezuela, which are under American sanctions.
Petrol is scarce in Venezuela due to a near-complete breakdown of the Opec nation's 1.3m barrel-per-day refining network.
Washington is considering measures in response, a senior US official said.
The shipment has drawn condemnation from Venezuela's opposition, which is concerned about growing ties between Iran and socialist President Nicolas Maduro, who has overseen a six-year economic crisis.
The shipments are bringing enough fuel for a month of consumption at current rates in the nation, once a prominent fuel exporter.
"[The ruling party] is trying to turn an embarrassment into an epic victory," said Oscar Ronderos, a legislator on the opposition-controlled National Assembly's energy commission.
The US accuses Iran and other countries of propping up Mr Maduro. It is among nearly 60 nations that back opposition leader Juan Guaido as Venezuela's legitimate president, contending that Mr Maduro illegitimately won a 2018 election that banned his most popular opponents.
In a new relationship between Caracas and Tehran, Iran recently flew shipments of an important chemical needed to help jump start a Venezuelan oil refinery and produce petrol.
Iranian President Hassan Rouhani said on Saturday that the US should not to interfere with the shipment of oil bound for Venezuela.
Mr Rouhani said that the US had created "unacceptable conditions" in different parts of the world, but that Iran would "by no means" be the one to initiate conflict.
"If our tankers in the Caribbean or anywhere in the world face any problems caused by the Americans, they will face problems as well," he said. "We hope the Americans will not make a mistake."
US officials had announced no plans to try to intercept Iran's tankers. However, the Donald Trump administration has increased pressure on Mr Maduro, recently offering a $15 million (Dh18.4) bounty for his arrest after a US court indicted him as a drugs trafficker.
The US also recently sent several ships, including naval destroyers and other combat vessels, to patrol the Caribbean on what American officials said was a mission to combat the drug trade. The Maduro government considers it a direct threat.
Mr Maduro holds on to power with support from Venezuela's military and his international allies, including Cuba, Russia, and China. The US says these nations are engaged in "malign activities and meddling" around the world.
"We will not abide by their support of the illegitimate and tyrannical regime of Nicolas Maduro," the Trump administration said, citing its "maximum pressure" campaign against the socialist leader that would "continue until Maduro's hold on Venezuela is over".