US President Donald Trump has responded to blistering criticism from Republican senator-elect Mitt Romney.
Mr Trump said he would “much prefer that Mitt focus on border security and so many other things where he can be helpful”.
Mr Romney, incoming Utah senator and former 2012 Republican presidential candidate, targeted Mr Trump’s policies and character in a column for The Washington Post.
He wrote that Mr Trump has “not risen to the mantle of the office”.
Mr Trump tweeted: “Here we go with Mitt Romney, but so fast! Question will be, is he a Flake? I hope not. Would much prefer that Mitt focus on Border Security and so many other things where he can be helpful. I won big, and he didn’t. He should be happy for all Republicans. Be a TEAM player & WIN!”
The Flake reference was to retiring senator Jeff Flake, a Republican who has been a Trump critic.
Mr Romney praised some of Mr Trump’s policy decisions in the article, but added: “With the nation so divided, resentful and angry, presidential leadership in qualities of character is indispensable. And it is in this province where the incumbent’s shortfall has been most glaring.”
He said he does not intend to comment on every Trump tweet, but promised to “speak out against significant statements or actions that are divisive, racist, sexist, anti-immigrant, dishonest or destructive to democratic institutions”.
The former Massachusetts governor will be sworn into the Senate on Thursday.