Financial crisis in Argentina unnerves Latin American and world markets; the question: Is Brazil next?

The rapid decline and revaluation of the Argentinian peso has sent shock waves thorugh Latin American economies. It is troubling countries outside the region as well and is blamed in part for large declines Thursday and Friday on the world’s largest stock exchanges.

Cities across Argentina are still unnerved by all the looting that broke out last month after police officers went on strike, protesting salaries eroded by rampant inflation. Residents fumed over blackouts that left them sweltering during a recent heat wave. Then the currency plunged this week, the steepest decline since the nation’s economic collapse in 2002, stirring fears that another major financial crisis could be around the corner.

“In 80 years, there’ve been tough times, but it’s never been as bad as this,” Irma Herrera, 80, a retired psychologist, said Friday after the government announced that it would make it easier for Argentines to buy dollars amid the financial upheaval.

“I’m not going to buy dollars when my monthly pension doesn’t even stretch to buy food,” Ms. Herrera said.

In a matter of days, Argentina has become a symbol of the economic stresses mounting in developing countries around the world. Fears are rising that the demand for commodities, a centerpiece of Argentina’s economy, is weakening in places like China, a slowdown that could threaten developing nations.

At the same time, the prospect of better returns in the United States is drawing money out of the developing world and battering currencies from Turkey to Russia to South Africa.

The worries over contagion are spreading. In Brazil, the country’s powerful automobile industry is bracing for the problems in Argentina, one of Brazil’s biggest export markets. But beyond the global forces at play, the financial swings this week have called attention to the particular challenges for some of Latin America’s most vulnerable economies.

“There’s something that’s happening all over Latin America, which is that the region is coming to the end of its commodities boom,” said Francisco Rodríguez, an economist with Bank of America Merrill Lynch. “Some countries are more vulnerable than others, and definitely the Venezuelas and Argentinas of the world are more vulnerable. Markets are getting very nervous about what will happen to them if you enter a period of a slump in commodities prices.”

This week in Venezuela, the government announced what amounted to a partial devaluation and new currency controls. On Friday, travel agents said several airlines had either stopped selling tickets over the last few days or made only a very limited number of seats available. Ecuador’s Tame airline and Air Canada stopped service to Caracas at mid-week although Tame resumed service on Friday after Venezuela’s central bank promised payment.

The airlines say they have $3.3 billion in revenues in Venezuelan banks that the government has not let them take out of the country. They worry that the value of that money, which is still in local currency, could shrink significantly.

“This is one of the high points when you speak to airline C.E.O.’s,” said Peter Cerda, regional vice president for the Americas of the International Air Transport Association. “What keeps them up at night is exactly this. What their money’s worth today, it might not be worth tomorrow.”

On Friday, Venezuela’s government also put new limits on the dollars it promises to sell citizens traveling abroad, with a cap of $700 per trip to Florida, compared with $2,500 for travel elsewhere in the United States.

“It’s madness,” said Antonio Miglio, 42, a businessman, who flies to Orlando, Fla., every year with his family to go shopping. “The government made this decision because of the economic crisis, but this will only make the crisis worse.”

In Argentina, the pressures have been building for years. Generous social spending after the crisis in 2002, like freezing household electricity rates and making payments to poor families, has widened Argentina’s deficit. The country has been printing money, fueling inflation. The issue has been so polemical that the government has been in a fight for years over how high inflation really is; independent economists say it reached 28 percent in 2013, while officials say it was 10.9 percent.

Argentina’s economy is still expected to grow at 2.8 percent this year, according to the International Monetary Fund, but growth has slowed significantly from recent years, and capital flight has been a longstanding problem. Given that the government has nationalized businesses like YPF, the country’s biggest oil company, some investors have pulled back, and many people here have tried to take their money out of the country.

To prevent that exodus, the authorities have tried to restrict access to foreign currency. Now, with a nearly 20 percent drop in the value of the peso just this week, the government said Friday that it would allow people to buy dollars with greater ease. The economy minister described the shift as a response to “psychosis” in Argentina’s financial markets.

“The government is trying to find a way out of the mess it got into,” said Fausto Spotorno, an economist at Orlando Ferreres y Asociados in Buenos Aires. “But there’s so much more to do, like tackle inflation.”

Rather than stemming the anxiety, the government’s announcement on Friday seemed to sow confusion.

“This is all improvised,” said Antonio López, 63, an administrator for an office building. “They don’t know what they’re doing.”

The economy minister, Axel Kicillof, lashed out at financial analysts who contended that the peso might weaken further, calling them “great liars.” In comments to an Argentine radio station, he attributed the sharp fall in the peso to a “speculative attack” put into motion by the oil giant Royal Dutch Shell.

“The authorities in Argentina are suffering from low credibility,” said Alberto Ramos, an economist at Goldman Sachs. “The situation can get as bad as they want to make it.”

The streets of downtown Buenos Aires were bustling but calm on Friday, with more dark humor than signs of panic. “Great, we can buy dollars now,” said Nicolás Titaro, 61, a company treasurer. “We just need salaries that let us.”

Other Argentines wondered whether another period of economic turmoil loomed. “It’s always the same here, a crisis every 10 years,” said Marcelo Rosales, 50, a security guard. “The government will not assume the political cost of dealing with this. It is only healing minor cuts with plasters.”

Photo caption: Argentina President Cristina Fernández de Kirchner