President Trump is preparing to threaten Mexico with new tariffs as part of an attempt to force the country to crack down on a surge of Central American migrants seeking asylum in the United States, according to three administration officials who described the “big league” statement Trump teased to reporters Thursday morning.

Trump is planning to make the announcement Friday but some White House aides are trying to talk him out of it, arguing that such a threat would rattle financial markets and potentially imperil passage of the USMCA trade agreement, according to these officials, who requested anonymity in order to discuss internal administration plans.

A senior White House official, however, said there is broad support across the administration to push Mexico further and that Trump’s announcement is likely to happen Friday. This official said aides were meeting late Thursday to make sure the implementation is ready.

The White House on Thursday sent a draft of the trade deal to Congress in an attempt to expedite its passage. The deal aims to curb the type of tariffs Trump is now threatening to impose if Mexico does not stop the migrants.