House Speaker Paul Ryan, the country's highest-ranking Republican in office, said he is "not ready" to endorse Donald Trump for a potential GOP presidential nomination.

"I hope to support our nominee," Ryan said on CNN. "I'm just not there right now. We have work to do. Our nominee has work to do." Ryan is the current chariman of the Republican National Convention and has gone on record repeatedly saying he would support the GOP's nominee.

Trump responded with a statement Thursday evening. "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!"

"Lincoln and Reaganesque"

During Thursday's CNN interview, Ryan had this to say about Trump: "We hope that our nominee aspires to be Lincoln and Reaganesque," someone who "appeals to a vast majority of Americans."

Ryan later hit the campaign trail at the Veterans Terrace in Burlington for a gathering of about 100 supporters as he stumped for Republican Sen. Ron Johnson, who is seeking re-election versus Democratic challenger Russ Feingold. According to a Journal Sentinel report from Thursday's event, neither Ryan nor Johnson spoke about Trump.