El Salvador has ordered Venezuela's diplomats to leave the country within 48 hours, in line with President Nayib Bukele's position that the Venezuelan government of Nicolas Maduro is illegitimate.
More than 50 countries have switched their recognition to national assembly speaker Juan Guaido as Venezuela's legitimate acting president.
Before his election in June, Bukele said he would maintain a "distant" relationship with Caracas and close ties with the United States, which has demanded Maduro's exit from power.
"The government of El Salvador expels the diplomatic corps from the regime of Nicolas Maduro," Bukele said in a statement posted his Twitter account late Saturday.
US Ambassador Ronald Johnson reacted warmly to the decision.
"We applaud the government of President Nayib Bukele for ensuring that El Salvador is on the right side of history," he said on Twitter.
The leftist government of President Nicolas Maduro has jailed opposition leaders and is accused of using torture and arbitrary arrests as it struggles to hold on to power amid a collapsing economy.
But his government still has strong support at the UN, from Russia and China in particular.
Maduro has barred overseas travel by Guaido, who in April tried to lead a military mutiny that quickly fizzled out.