This marks the highest level over a four week period in five years.
During the first months of the pandemic, the Trump administration placed a public health law that allowed border officials to turn away migrants encountered at the border.
While this law is still in order under the Biden administration, unaccompanied children are exempt from the order and can legally remain in the U.S. pending immigration cases.
The first months of the Biden administration have seen a surge in migrants arrested at the southern border, resulting in more than 3,200 unaccompanied migrant children in the custody of Customs and Border Protection as of March 9.