SAN SALVADOR (Reuters) - The United States and El Salvador have worked out “operational details” of an agreement in which El Salvador would take in certain migrants who had sought asylum at the U.S. border, the U.S. Department of Homeland Security (DHS) said on Tuesday. The deal, called the Asylum Cooperative Agreement (ACA), was first announced in September 2019 and is similar to “safe third country” deals President Donald Trump’s administration has sought with several Latin American countries to curb migration, especially from Central America. Trump in recent weeks has made a last-minute push to implement tougher immigration rules, a central focus of his administration, despite signs that his successor, Joe Biden, will aim to quickly undo them. Biden has also pledged $4 billion to tackle the root causes of migration in Central America. The acting DHS secretary, Chad Wolf, said in a statement the United States would help El Salvador expand its capacity to offer humanitarian protection. He did not explain details of the agreement, and it was not clear if any asylum-seekers would be sent to El Salvador before Trump’s presidency ends next month.