He crushed the primary competition, but Donald Trump still has work to do if he wants to win over key Republican.

FOX's Jared Halpern has more from Washington:

The man who will preside over the Republican Convention is not yet ready to throw his support behind Donald Trump.

Speaker of the House Paul Ryan telling CNN:

(Ryan) "I'm just not ready to do that at this point. I'm not there right now."

Ryan, the most senior elected Republican, says he may be able to eventually endorse his party's presidential nominee:

(Ryan) "What is required is that we unify this party. And I think the bulk of the burden on unifying the party will have to come from our presumptive nominee."

Ryan has been critical of some of Trump's campaign rhetoric, including a proposal to temporarily ban Muslims from entering the U.S.

In Washington, Jared Halpern, FOX News.

(AP Photo/Seth Perlman)
(AP Photo/Seth Perlman)

Donald Trump responded to Paul Ryan:

"I am not ready to support Speaker Ryan's agenda. Perhaps in the future we can work together and come to an agreement about what is best for the American people. They have been treated so badly for so long that it is about time for politicians to put them first!"