Donald Trump has shrugged off a stinging personal attack on his presidency from senior fellow Republican Mitt Romney.
Mr Romney, who stood and lost for the Republicans against Barack Obama in 2012, suggested in an article that Mr Trump was not fit to be president.
Mr Trump had not “risen to the mantle”, he wrote in the Washington Post.
The winner of the 2016 presidential election hit back by tweeting, “I won big and he didn’t.”
Mr Trump drew a comparison with Jeff Flake, an outgoing Republican senator who also attacked him last year.
But the president sounded conciliatory, calling for Mr Romney to be a “team player”.
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The timing of the article, just two days before Mr Romney is sworn in as senator for Utah, has prompted some to speculate he is positioning himself as a challenger to Mr Trump for the Republican presidential nomination.
What did the opinion piece say?
In the article, Mr Romney praised many of Mr Trump’s policies, such as his tax reforms and appointment of conservative judges, and his crackdown on “China’s unfair trade practices” – polices which he said “mainstream Republicans” had promoted for years.
But he went on to say: “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.”