Paul Ryan says he is not yet ready to support Donald Trump for president

The speaker of the House says he is waiting to see if Donald Trump will "champion" conservative principles.

Paul Ryan has joined a number of other high-ranking Republicans and said that he's not ready to support Donald Trump for president of the United States.

Mr Ryan, the speaker of the House of Representatives, did not close the door on supporting Mr Trump, but said he needs to see more from the bombastic candidate.

"I want to see verifcation that our conservative principles will be championed," Mr Ryan said. "We're not there yet.

Paul Ryan, speaker of the House, has said he cannot yet support Donald Trump for president. (Getty Images)

"I want to see us unify...but I don't know that that's going to happen."

Mr Ryan is the highest-ranking Republican to question Mr Trump, now the presumed Republican presidential nominee, but far from the first. John McCain said he's worried that Mr Trump's nomination will hurt his chances to be reelected to the Senate. Mitt Romney announced he will be skipping the Republican National Convention in Cleveland.

Since his Republican competitors left the race earlier this week, Mr Trump has said he will start working more closely with Republican leadership as the general election gets closer.

In response to the speaker, Mr Trump said he wasn't sure he could support Mr Ryan's plans.

“I am not ready to support Speaker Ryan's agenda," Mr Trump said in a statement. "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.”

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