President Donald Trump said Monday that he would only be willing to donate $1 million to charity if he could personally test the DNA of Sen. Elizabeth Warren (D-Mass.) to determine whether she has a Native American ancestor.

Trump said in July that he would donate $1 million to a charity of Warren’s choice if she could prove her claim that she had Native American heritage. Warren on Monday released the results of a DNA test to The Boston Globe, and an expert told the publication there was “strong evidence’’ that the senator has a Native American ancestor.

Warren said she’d like Trump to make his donation to the National Indigenous Women’s Resource Center, a nonprofit that seeks to protect native women from domestic violence. But when asked initially whether he would make good on his promise, Trump denied ever making it.

He later said he would make the donation under one condition.

“I will only do it if I can test her personally,” Trump said. “That will not be something that I enjoy doing.”

TRUMP says he will only pay 1 million dollars to charity for Warren if he can test her personally: "I will only do it if I can test her personally. That will not be something that I enjoy doing" — Saagar Enjeti (@esaagar) October 15, 2018

It is not clear what he meant when he said he would personally test Warren’s DNA.

The president also said the senator “owes the country an apology” for claiming indigenous heritage.

TRUMP on Warren: "She owes the country an apology. What is the percentage? 1/1000th?" — Saagar Enjeti (@esaagar) October 15, 2018

Warren’s ancestry is largely European but “the results strongly support the existence of an unadmixed Native American ancestor” six to 10 generations ago, according to Carlos D. Bustamante, a Stanford University professor who analyzed the results.

Warren would be 1/1,024th Native American if the ancestor was 10 generations back, according to the Globe.