The policy had allowed children to seek asylum without having to make the perilous journey to the US.
Amid calls from lawmakers, advocates, and the press to allow media inside, Mayorkas blamed the pandemic and said the DHS would release "footage."
Homeland Security's Alejandro Mayorkas defended the Biden administration's policy of expelling families and adult migrants, but not young arrivals.
FEMA will assist in a 90-day "government-wide effort" to respond to the thousands of migrant children arriving in the US.
Parents separated from their children by the Trump administration are now eligible to be reunited inside the United States.