The high-profile move comes as DeSantis seeks re-election in November and has been mentioned as a possible presidential candidate in 2024. It mirrors campaigns by the Republican governors of Texas and Arizona to push responsibility for a record number of border arrivals to Democratic strongholds across the United States, including Washington, D.C., New York City and Chicago.

Governor of Texas Greg Abbott is another Republican facing re-election in November, and has bused more than 10,000 migrants from his state since April. On Thursday morning, two buses from Texas dropped migrants off in a part of the city near Vice President Kamala Harris' official residence with no warning, according to one volunteer Ashley Tjhung.

Pierre criticized the drop-offs.

"The fact that Fox News and not (Department of Homeland Security), the city or local NGOs were alerted about a plan to leave migrants, including children, on the side of a busy DC street makes clear that this is just a cruel, premeditated political stunt," she said.

Abbott's office did not immediately respond to a request for comment.