Paul Ryan, the top U.S. elected Republican, on Wednesday continued to withhold his support from Donald Trump for the Republican Party's presidential nomination, saying he is not ready to endorse the real estate billionaire, a political neophyte.

Ryan, the speaker of the U.S. House of Representatives, brushed aside reports that he was ready to endorse Trump during a meeting with reporters in the Capitol. "I haven't made a decision," he said, adding that he had no timetable for doing so.

The 46-year-old speaker is the only member of the Republican congressional leadership who has not formally embraced the presumptive Republican nominee. Ryan is expected to chair the party's nominating convention in July in Cleveland.