Trump fleshes out economic ideas after rivals exit White House race

U.S. House Speaker Paul Ryan (R-WI) holds his weekly news conference at the U.S. Capitol in Washington, U.S., April 28, 2016. REUTERS/Jonathan Ernst

WASHINGTON (Reuters) - The top elected U.S. Republican, Paul Ryan, said on Thursday he was not ready to endorse Donald Trump, a sign of the challenges the party's presumptive presidential nominee faces rallying the Republican establishment behind his White House bid.

Ryan, the speaker of the U.S. House of Representatives, said conservatives wanted to know if Trump shares their values.