By Hugh Bronstein and Maximilian Heath
BUENOS AIRES (Reuters) - President Barack Obama and the first lady will visit the lake-side Patagonian tourist city of Bariloche later this month during an official trip to Argentina, a U.S. diplomat told local radio on Friday.
The trip will follow the couple's visit to Cuba on March 21 and 22, another major step toward ending decades of animosity between former Cold War foes.
They will meet with newly elected Argentine President Mauricio Macri on March 23 and fly to Bariloche the following day, Kevin Sullivan, deputy chief of mission at the U.S. embassy in Buenos Aires, told Radio Mitre.
The stopover in ski-destination Bariloche, known for its crystal clear lakes and panoramic mountain vistas, appeared to be first lady Michelle Obama's idea, Sullivan said.
"I believe she heard what Bariloche is like ... and it seemed to her it would be a good place to share a little family time," Sullivan said.
Relations have improved between Argentina and the United States since Macri took office in December. Macri has moved to open Latin America's No. 3 economy to foreign investment by ditching trade and currency controls enacted by his predecessor.
"It seems to us to be a good moment for President Obama to get to know Argentina and have a dialogue with President Macri," Sullivan said. The agenda will include international cooperation, terrorism, human rights and energy investment.
Argentina has some of the world's largest untapped shale oil and natural gas formations. China is a major investor in Argentina's energy and grains sectors.
March 24 will be the 40th anniversary of the 1976 coup that installed a military dictatorship, which the United States initially supported. Argentina returned to democracy in 1983.
Adolfo Perez Esquivel, who won the Nobel peace prize for his human rights work during the dictatorship, wrote an open letter to Obama this week saying that if the U.S. president stayed in Buenos Aires on the 24th, many Argentines would see that as "a provocation."
Marches and demonstrations in honor of the victims of the military junta are planned for that date in the Argentine capital.
(Reporting by Hugh Bronstein; Editing by Richard Chang)