U.S. House Speaker Paul Ryan said on Monday he would step down as chairman of the Republican Party's July convention if presumptive Republican nominee Donald Trump asked him to do so, a Milwaukee Journal Sentinel reporter said on Twitter.

".@SpeakerRyan on whether he'd step down as convention chair if Trump asks: I'll do whatever he asks me to do," Christian Schneider, one of the newspaper's columnists, tweeted.

Ryan also said in the interview he is steadfastly opposed to a third-party candidate, even if it were 2012 party nominee Mitt Romney, Schneider said in another tweet.