President Joe Biden accused Republicans of using people “as props,” an apparent reference to GOP governors sending migrants from their states to liberal enclaves.

“Republicans are playing politics with human beings,” Biden said Thursday at the Congressional Hispanic Caucus Institute Gala in Washington, without naming the governors or describing their actions. “What they’re doing is simply wrong. It’s un-American. It’s reckless.”

Biden said immigration officials have processes in place to manage migrants at the border in a safe, orderly way and “Republican officials should not interfere with that process by waging these political stunts.”

The president spoke hours after two buses sent by Texas Governor Greg Abbott arrived near Vice President Kamala Harris’s residence in Washington. On Wednesday, two planes dispatched by Florida Governor Ron DeSantis landed on Martha’s Vineyard, a Massachusetts island known as an enclave for wealthy vacationers.

Republican leaders have said the Biden administration’s immigration policies entice migrants to cross into the U.S. and overwhelm communities along the southern border. The White House denies those claims and says migration is brought about by factors like violence and poor economic conditions in Central America and Mexico, exacerbated by the coronavirus pandemic.