Speaker John A. Boehner said Republicans will fight “tooth and nail” against President Barack Obama’s plans to act on immigration by himself, and didn’t rule out a government shutdown.

“We’re going to fight the president tooth and nail if he continues down this path,” the Ohio Republican said at a press conference introducing the new GOP leadership team. “This is the wrong way to govern. This is exactly what the American people said on Election Day they didn’t want. And so, all the options are on the table.”

Boehner is facing pressure from conservatives to pre-emptively defund any amnesty, but that could lead to a shutdown fight.

“We’re going to have conversations with our members and when we have a decision, we’ll let you know. … Our goal here is to stop the president from violating his oath of office and violating the Constitution. It’s not to shut down the government.”