A senior Donald Trump aide has publicly criticised Mitt Romney and questioned his loyalty, throwing into doubt his status as front-runner to become secretary of state.

Kellyanne Conway, who managed Mr Trump’s campaign and now serves as a top adviser, wrote on Twitter that she had received a “deluge of social media and private” communications about a potential Romney appointment. She followed up with a post about the importance of loyalty in a secretary of state, something Mr Romney has never been accused of harbouring towards Mr Trump.

The messages came after speculation that Mr Romney had reservations about joining the Trump administration, even in such a coveted role.