An Iranian news agency close to the elite Revolutionary Guards said that there would be repercussions if the United States acts "just like pirates" against an Iranian fuel shipment to Venezuela.
A senior official in President Donald Trumps administration told Reuters on Thursday the United States was considering measures it could take in response to Iran's shipment of fuel to crisis-stricken Venezuela.
The oil sectors of Iran and Venezuela – members of Opec that both are deeply at odds with the United States – are under tough US sanctions. The Trump administration official declined to specify the measures being weighed but said options would be presented to Mr Trump.
"If the United States, just like pirates, intends to create insecurity on international waterways, it would be taking a dangerous risk and that will certainly not go without repercussion," the Nour news agency said early on Saturday.
At least one tanker carrying fuel loaded at an Iranian port has set sail for Venezuela, according to vessel tracking data from Refinitiv Eikon on Wednesday, which could help ease an acute scarcity of petrol in the South American country.
The Iran-flagged medium tanker Clavel earlier on Wednesday passed the Suez Canal after loading fuel at the end of March at Iran's Bandar Abbas port, according to the data.
"News received from informed sources indicate that the US Navy has sent four warships and a Boeing P-8 Poseidon from the VP-26 squadron to the Caribbean region," Nour said.
Venezuela is in desperate need of petrol and other refined fuel products to keep the country functioning amid an economic collapse that has occurred under socialist President Nicolas Maduro. It produces crude oil but its infrastructure has been crippled during the economic crisis.
A Venezuelan official said last month that his country had received refining materials through plane from Iran to help it start a unit at the 310,000 barrels-per-day Cardon refinery, which is necessary to produce petrol.