Critics say the tanker is just one example of the socialist government’s corruption and mismanagement that has bankrupted the nation's petroleum industry.
"The government is using political prisoners as bargaining chips,"said one Caracas-based political analyst after the announcement.
Security operations in the country have killed at least 1300 people since the start of the year,UN rights office says.
The first Iranian ship to arrive is trailed by four other tankers. The shipments,however,only carry enough fuel for two or three weeks,analysts say.
Venezuela's ambassador to the United Nations,Samuel Moncada,also lashed out at the US,saying any attempt to stop the tankers would be illegal.
Maduro aired a video of a 34-year-old Texas native who claims he signed a contract with a Florida-based company to train rebel troops and carry out the assault.
In a state television address,The Venezuelan President showed what he said were the passports and other ID cards of two employees of a Florida-based company.
Seven sources,representing both sides of the country's deep political divide,say allies to President Nicolas Maduro and rival Juan Guaido are in talks.
The US has openly said President Nicholas Maduro will never be allowed to govern again.
Maduro blasted back by accusing the US and Colombia of"giving orders to flood Venezuela with violence."
More than 4.5 million Venezuelans have fled their nation's crisis in recent years,with nearly 2 million seeking jobs,shelter and healthcare in Colombia.