Nonprofit news organisation ProPublica published audio on Monday of children crying out for their parents at a US Customs and Border Protection facility.
The Trump administration is not backing down from its controversial policy of splitting up families that try to cross the US-Mexico border without documentation.
The practice has drawn criticism from across the political spectrum, but President Donald Trump says he will not allow America to become a "migrant camp".
Al Jazeera's Heidi Zhou-Castro report Washington, DC.
