The Iranian president, Mahmoud Ahmadinejad, is due to touch down in Venezuela on Sunday on the first leg of a Latin American tour aimed at lifting his regime out of international isolation and bolstering its sanctions-hit economy.

Ahmadinejad, who is facing growing economic discontent at home and pressure from the west over Iran's disputed nuclear programme, will also visit Nicaragua, Cuba, Ecuador and possibly Guatemala in a search for new and improved economic partnerships to reduce the impact of sanctions. The five-day Latin America visit is scheduled to start in the Venezuelan capital, Caracas, with meetings with president Hugo Chávez, a long-time ally.

Ahmadinejad is then expected to travel to Managua for the swearing-in of the Nicaraguan president, Daniel Ortega, before travelling to Cuba and Ecuador. Reports suggest he may also visit Guatemala.

The president's entourage is expected to include the energy minister, Majid Namjoo, who has said the tour is aimed at promoting commercial ties with Latin American countries. Analysts view Ahmadinejad's excursion as a reaction to growing economic difficulties at home and political isolation abroad.

Michael Shifter, president of the Washington-based thinktank Inter-American Dialogue, said Iran had economic and geopolitical agendas in Latin America.

"Iran has real economic difficulties and is isolated, so the trip makes sense in that context," he said. "Latin America, in contrast, is in pretty good economic shape and is increasingly active in global, diplomatic affairs."

Maria Teresa Romero, professor of international studies at the Universidad Central de Venezuela, said the trip was also intended as a warning signal to Washington.

"That Iran's president has chosen to visit the region – and only the more staunch political opponents to the US – at a moment when tensions between the US and Iran are escalating is a challenge, a threat, from the Iranian government to the US that sends a clear message: 'We can go to your backyard when we want to,'" she said.

Iran is grappling with a range of domestic and international problems.Its currency, the rial, has plunged to a record low in recent weeks, causing mayhem at the Iranian stock market and prompting fears over the future effects of the sanctions on the economy.

High unemployment, political power struggles and fears of unrest before the parliamentary elections in March have made the domestic political atmosphere increasingly tense.

At an international level, Iran has resorted to sabre-rattling and threatening countries involved in a campaign to bring sanctions against its central bank and impose a ban on the import of its oil.

Iran raised the stakes, warningthe west it might close the strait of Hormuz, a strategically important passageway in the Gulf through which one fifth of the world's oil is transported, should greater sanctions on its oil be imposed.

Latin America has become an increasing priority for Ahmadinejad since his election in 2005. New embassies have opened in six countries, while state-run Press TV has also been beefing up its presence in the region, with correspondents in Caracas and more recently Sao Paulo.

On the eve of Ahmadinejad's visit, one Press TV report said: "The promotion of all-out co-operation with Latin American countries is among the top priorities of the Islamic republic's foreign policy."

But Shifter said Iran's president should not hope for big advances during his tour. Ahmadinejad will not visit Brazil, the regional economic powerhouse, as he did during his previous visit in 2009 – an indication that relations have cooled since Dilma Rousseff took over as president.

"Iran should probably keep its expectations in check. If Iran's goal is to extend its influence, Latin America does not offer a hospitable environment. It is telling that the larger, more significant countries are not part of Ahmadinejad's itinerary. These countries may want greater independence from Washington, and may be flexing their muscles a bit on the global stage, but they are not keen to be aligned strategically with Tehran," he said.

Romero said that in the case of Hugo Chávez, who faces a tricky presidential election in October, the visit could even backfire.

"This is an electoral year in both the US and Venezuela, and I would be surprised if the Republicans don't use this kind of event to exert more pressure on the Obama administration. I think sanctions against Iran are likely to strengthen, but I also think they could be extended to Venezuela."