President Donald Trump is criticizing Republican House Speaker Paul Ryan for dismissing his call to end so-called birthright citizenship for the children of non-U.S. citizens born in the country.

Trump tweets that Ryan "should be focusing on holding the Majority rather than giving his opinions on Birthright Citizenship, something he knows nothing about!"

Ryan, who is retiring from Congress after this term, said Tuesday that Trump "obviously" could not end birthright citizenship through executive action, and legal scholars are divided on whether even Congress can do it by legislation.

Trump appears to be backing off his desire to do it by executive action, tweeting, "Our new Republican Majority will work on this, Closing the Immigration Loopholes and Securing our Border!"