President Donald Trump on Monday conceded that the United States may fund his proposed wall on the U.S.-Mexico, but insisted that Mexico will “ultimately” pay for his proposed physical barrier.

“One way or the other, Mexico is going to pay for the wall. That’s right. It may be through reimbursement, but one way or the other Mexico will pay for the wall,” Trump said at a joint press conference with Finnish President Sauli Niinistö.

He said Mexico “is being reluctant” to pay because the nation has “had one of the sweetest deals for years.”

“We need the wall, it’s imperative. We may fund it through the United States, but ultimately Mexico will pay for the wall,” Trump said.

He did not specify how that would happen.

Trump on Sunday made a similar claim in a tweet insisting Mexico would pay for the wall “through reimbursement/other.”

The Mexican government on Sunday offered Texas aid and solidarity as the state suffered massive flooding and destruction from Hurricane Harvey, but said it would not pay “under any circumstances” for Trump’s proposed border wall.