"If our tankers in the Caribbean or anywhere in the world face trouble caused by the Americans, they [the US] will also be in trouble", Rouhani said in a telephone conversation with Qatar's Emir Sheikh Tamim bin Hamad Al Thani, the semi-official news agency Mehr reported.
The shipments have caused a diplomatic standoff between Iran and Venezuela and the United States, as both nations are under USA economic sanctions.
A senior USA official toldReuters on May 14 that the Trump administration is reviewing measures it could take in response to the shipment.
Five Iranian tankers apparently consisting of at least $45.5 million in value of gasoline and similar items are now sailing to Venezuela in defiance of US sanctions, reported the Associated Press on Sunday.
But a Pentagon spokesman, Jonathan Hoffman, said on Thursday he was not aware of any operations related to the Iranian cargoes.
He stressed that his country is not interested in escalation but would take necessary action to defend its sovereignty and safeguard its national interests.
It has been navigating with its satellite signal on since it passed the Suez Canal earlier this month.
US envoy blasts Iranian oil shipments to Venezuela, breaking sanctions
Iran-flagged tanker Fortune, the first in the flotilla, was approaching the Caribbean Sea.
In a tweet on Friday, Moncada announced that Venezuela had alerted the UN Security Council and its Secretary General Antonio Guterres of "the threat of imminent use of military force by the United States against Iranian vessels carrying Venezuelan-directed gasoline".
Venezuela's defense minister said its military will escort the Iranian tankers once they reach the nation's exclusive economic zone.
A force of United States vessels, including Navy destroyers and other combat ships, is now patrolling the Caribbean on a drug interdiction mission.
· any other goods or services relating to the maintenance, supply, bunkering, and docking of such vessels. Fuel sales at stations declined to about 40,000 bpd due to rationing, according to analysts.
While a cold war with China is working its way towards the inevitable, another situation is developing that could lead to physical clashes between Iran and the United States over the former's attempts to ship fuel to Venezuela amid the collapse of its refining industry.