President Donald Trump has pulled out of his first trip to Latin America and is sending Mike Pence to the Summit of the Americas instead.
The White House said on Tuesday morning that the president was staying in Washington to deal with the Syria crisis.
“President Trump will not attend the 8th Summit of the Americas in Lima, Peru or travel to Bogota, Colombia as originally scheduled," said Sarah Huckabee Sanders, the press secretary.
"At the president’s request, the vice president will travel in his stead.
"The president will remain in the United States to oversee the American response to Syria and to monitor developments around the world.”
Mr Pence has previously served as Mr Trump's envoy to Latin America, visiting Colombia and holding meetings with President Juan Manuel Santos, an important US ally in the fight against the drug trade.
Mr Pence has also frequently had to paper over somewhat fraught relations with the region, damping down fears of military invasion after Mr Trump floated the idea of sending troops into Venezuela, and reassuring Latin American leaders that the economic and strategic partnership remained important.
The Summit, held in the Peruvian capital Lima, had been eagerly anticipated by Latin American leaders, wanting to get their first face-to-face encounter with Mr Trump.
The last Summit, held in Panama in April 2015, saw Barack Obama hold a bilateral meeting with Raul Castro - the first time the two countries' leaders had met since the Cuban Revolution.
Mr Obama told the assembled Latin American rulers that America wanted to help their countries develop economically, but that the old era of unwanted American interference were over.
He told the forum that "the days in which our agenda in this hemisphere presumed that the United States could meddle with impunity, those days are past".
But he also gave a defiant and markedly personal defence of Washington's support for opposition groups.
"We've stood up, at great cost, for freedom and human dignity, not just in our own country, but elsewhere. I'm proud of that," Mr Obama said, citing the US civil rights movement.
"As you work for change, the United States will stand up alongside you every step of the way."
Mr Trump's message of America First, however, was expected to be far less embraced by the attendees.
The week leading up to the Summit, which was first held in Miami in 1994, was marked by Mr Trump's decision to send US National Guard troops to the border with Mexico, and a fierce rebuke by the Mexican president, Enrique Pena Nieto, to Mr Trump's words.
The Summit is being held under the theme of reducing corruption.
But it comes at a highly sensitive time of transition in the region, with presidential elections in Mexico, Brazil, Venezuela and Cuba - where the country will, from next week, be led by someone other than a Castro for the first time since 1959.
Nicolas Maduro, the Venezuelan president, is aiming for re-election in May in a vote which much of the opposition has vowed to boycott.
Spurned by his fellow Latin American leaders, Mr Maduro has had his invitation revoked - but he vows to attend anyway, setting the stage for a dramatic showdown in Peru.