The United States is facing the biggest surge of migrants at its southwestern border in 20 years, the homeland security secretary said on Tuesday as the Biden administration races to handle an influx of children trying to cross the US-Mexico border alone.

The number of attempted border crossings by people from Central America and Mexico has steadily increased since April 2020 and most single adults and families are being turned away, Homeland Security Secretary Alejandro Mayorkas said.

Poverty, violence and corruption in the Mexico and the Northern Triangle - Guatemala, Honduras and El Salvador - have led people to seek a better life in the United States for years, and there have been surges in the past...