Iranian Foreign Minister Mohammad Javad Zarif arrived in Venezuela on Wednesday at the start of a Latin American tour that will also take him to Cuba and Bolivia.
"Each high-level visit deepens our strategic alliance, our brotherhood", Venezuelan foreign minister Jorge Arreaza tweeted on 4 November after welcoming his Iranian counterpart on his arrival in the South American country.
"Venezuela and Iran have shown solidarity and courage in the face of the aggressions," added Mr Arreaza, in an apparent reference to the US sanctions against both countries.
According to the Venezuelan news agency AVN, the parties will discuss ways of "deepening strategic bilateral cooperation relations".
Tehran has become a crucial ally for Caracas as Washington tightens sanctions aimed at forcing Venezuelan President Nicolas Maduro out of power.
Juan Guaidó was recognised by the United States and other Western countries as Venezuela's legitimate leader in January 2019 after what most consider to be a bogus election that gave Maduro a new mandate.
In recent months, Iran has supplied Caracas with humanitarian aid and fuel, while Venezuela's own oil production has plummeted.
Zarif will also travel to Bolivia to attend the swearing-in ceremony of President-elect Luis Arce, and will travel to Cuba, according to Iranian and Venezuelan media.
Iran, Venezuela and Cuba have in common the fact that the US country's financial and trade sanctions were tightened during the most recent stage of President Donald Trump's administration.
Venezuela is the country with the largest number of oil reserves in the world, but the crisis it has suffered over the past two decades, which has led to misery for much of the population and even to the rationing and black market sale of petrol, has led it to seek oil outside the country. Teheran, which is close to Nicolas Maduro's government, has been responsible for providing Caracas with oil. The mismanagement and corruption of the state oil company PDVSA in recent years has led to the collapse of its refineries.
This alliance has been understood by the United States, first, as a violation of the sanctions imposed by Washington on Hassan Rohaní's government and, second, as contrary to the heavy-handed policy Washington is pursuing against Maduro's government in order to force it to fall.
At the beginning of October, as was the case in August, an oil tanker from Iran was sailing through Caribbean waters to the El Palito refinery in the state of Carabobo. These ships provide Caracas with fuel.
In mid August the US authorities seized four tankers allegedly carrying petrol from Iran to Venezuela, according to Reuters. Official sources, according to the agency, said the ships were seized peacefully and the cargo they were carrying was transferred to other vessels for shipment to the United States.
The United States re-imposed the sanctions on Iran despite the fact that the United Nations Security Council had previously refused to extend the embargo imposed on Tehran and provoked further criticism from the Iranian authorities against Washington. Tensions between the United States and Iran escalated sharply from 2018, when the Trump Administration decided to abandon the 2015 agreement, and these hostilities rebounded in January after the US army killed the head of the Quds Revolutionary Guard Force, Qassem Soleimani, in a bombing in Iraq.