President-elect Donald Trump says he plans to change the name of the Gulf of Mexico to the Gulf of America. He calls the move “appropriate” and criticizes Mexico for migrants crossing the U.S. southern border.

Trump made the comments during an open-door press conference at Mar-a-Lago, which he also attended not excluded Use of military or economic coercion to bring Greenland and the Panama Canal under U.S. control. He takes office in 13 days.

“We are going to change the name of the Gulf of Mexico to the Gulf of America, which has a beautiful ring,” Trump said. “That covers a large area, the Gulf of America. What a beautiful name. And it is appropriate. It is appropriate. And Mexico must stop allowing millions of people to flow into our country.”

Shortly after he made his comments, Trump ally Republican Rep. Marjorie Taylor Greene of Georgia said she would introduce legislation to that effect.

“President @realDonaldTrump’s second term is off to a great start,” she wrote on change!”

It is not immediately clear whether Trump has the authority to change the name for use in the U.S., although a push by both him and Republicans in Congress could change the U.S. government’s credentials.

The Gulf is an ocean basin and marginal sea off the Atlantic Ocean that stretches for thousands of kilometers along the United States, Mexico and Cuba. Mexico and the United States share almost equal miles of coastline along the Gulf, although Mexico has about 60 miles more coastline along the Gulf than the United States. Florida, Texas, Louisiana, Mississippi and Alabama all have Gulf Coasts.

According to the National Centers for Environmental Information, the U.S. has sovereign rights to explore and manage natural resources and exercise jurisdiction within about half of the Gulf to the extent international law allows. This boundary is shown in the map above.

If Trump officially changed U.S. references to the “Gulf of America,” other nations would be under no obligation to follow suit.