Iranian President Mahmoud Ahmadinejad left Sunday on a five-day Latin American tour, which U.S. officials have dubbed as a sign of desperation for the country heavily sanctioned over its controversial nuclear program.

Mr. Ahmadinejad will first visit Venezuela, followed by stops in Nicaragua, Cuba and Ecuador. Iranian state media quote the president as praising the “revolutionary spirit” of the leaders of those four countries.

In recent years, the Iranian president has courted leftist, populist and anti-American Latin American leaders, particularly Venezuelan President Hugo Chavez, much to Washington's dismay.

On Friday, U.S. officials urged Latin American countries not to deepen their ties with Iran. A State Department spokeswoman accused the Iranian government of being “desperate for friends” and of, what she called, “flailing around” to find new allies.

While on his trip, Mr. Ahmadinejad will meet with Venezuela's President Chavez and will attend the inauguration of Nicaraguan President Daniel Ortega.

The United States is expelling a Venezuelan diplomat amid reports that she discussed possible cyber-attacks on U.S. soil while she was stationed at her country's embassy in Mexico.

The State Department said Sunday it had declared Livia Acosta Noguera persona non grata and given her until Tuesday to leave the country.

There was no immediate reaction from the Venezuelan government.