U.S. President Donald Trump's top official at U.S. Immigration and Customs Enforcement has been reassigned as arrests and deportations have lagged expectations, a senior Trump official and two other sources familiar with the matter said on Friday.

President Donald Trump signed an executive order Wednesday to bar undocumented migrants from accessing public benefits, even though they’re already denied most federally funded programs—his latest move to tamp down on illegal immigration, though it wasn’t immediately clear which initiatives would be impacted.

The top official in charge of carrying out President Donald Trump’s mass deportations agenda has been reassigned amid concerns that the deportation effort isn’t moving quickly enough.