"Failing communist regimes in Venezuela, Nicaragua, and Cuba are driving a new wave of migration," a US official said.
In total, just under 158,000 people had encounters with southwest border officials in August.
"Failing communist regimes in Venezuela, Nicaragua, and Cuba are driving a new wave of migration across the Western Hemisphere, including the recent increase in encounters at the southwest US border," CBP Commissioner Chris Magnus said in a statement.
More than 55,000 people from the three, ostensibly socialist regimes were encountered at the southwest border in August, per CBP.
The fact that nearly half of all migrants encountered were from Nicaragua and South America, he said, represented a "staggering change."