House Speaker Paul Ryan praised presumptive Republican presidential nominee Donald Trump for releasing a list of potential Supreme Court nominees this week, but still refrained from endorsing him.

"The list of the judges was a very good step in the right direction," Ryan said when asked about when, if ever, he might endorse Trump. "We're making progress, but that's all I've got to say at this point."

Ryan said his aides are in contact with the Trump campaign and are working together, but he has stopped short of an endorsement. Ryan also refused to answer a reporter who asked whether he believed Trump is "qualified" to be president.

Ryan gave one of his standard answers to questions about Trump: "I'm not going to litigate this thing from the podium."

Ryan also declined to comment on Trump's declaration that if he becomes president he will work directly with North Korean dictator Kim Jong-un.