Ecuador has brought in new rules to stop Venezuelan migrants entering the country without a passport, leaving many stranded in neighbouring Colombia.
Thousands of Venezuelans fleeing their country’s economic and political crisis have been crossing into Ecuador from Colombia using only identity cards.
Most are heading south to join family members in Peru and Chile.
According to the BBC, Colombia has protested against the move, saying vulnerable people will be trapped on its side of the border.
In a separate incident, residents of a Brazilian town attacked a Venezuelan migrant camp on Saturday and drove the occupants back across the border.
Venezuela has suffered for years from high inflation and the chronic shortage of food and medicines.
More than a million Venezuelan migrants have entered Colombia in the past 15 months, according to official estimates, and more than 4,000 have been arriving at Ecuador’s border every day.
Ecuador’s decision to shut the border for those without passports went into effect on Saturday.
Many migrants, who have been walking or hitching rides for weeks and are exhausted by the time they reach the frontier, only carry ID cards.