Iran ignored warnings of retaliation from the US as the first of five Iranian tankers entered Venezuela's exclusive economic zone on Saturday.
The tanker, named Fortune, reached the Venezuela's territorial waters at around 7:40 pm after passing north of Trinidad and Tobago in the Carribean, according to vessel-tracking data.
Tareck El Aissami, Venezuela's economy vice president said: "The ships from the fraternal Islamic Republic of Iran are now in our exclusive economic zone."
Venezuelan state television showed images of a navy ship and aircraft preparing to meet it.
The defense minister had pledged that the military would escort the tankers once they reached Venezuela's Exclusive Economic Zone (EEZ) due to what authorities described as threats from the United States.
The five tankers are carrying a staggering 1.53 million barrels of gasoline and alkylate to Venezuela, according to both governments, and sources.
The desperately needed shipments have caused a diplomatic standoff between the United States and Iran and Venezuela, which are under US sanctions.
Iran has warned of repercussions from the potential interception of Iranian tankers by the US In a phone conversation with Emir of Qatar on Saturday, Iranian President Hassan Rouhani warned that the Islamic Republic will respond to any possible US aggression against Iranian oil tankers in the Caribean Sea or any other point in the world.
On May 20, Iran's Defense Minister Brigadier General Amir Hatami said that any US harassment of Iranian tankers will be met with a decisive response.
He said on Wednesday: "Any disruption for tankers is against international regulations and security," referring to the release of some reports on the threat of US officials to harass tankers carrying Iran's fuel to Venezuela.
"Both international organisations and countries that are sensitive to water regulations and security must react to this issue," he added.