Washington, Feb 20 (IANS): US President Donald Trump has endorsed former Republican presidential candidate Mitt Romney, who will run for a Senate seat from Utah state in November.

Despite their rivalry, Trump on Monday tweeted "all my support and endorsement" for Romney and considered him a "worthy successor" to Orrin Hatch, the current Utah senator who announced last month that he would retire after over four decades in office, reports Efe news.

"Mitt Romney has announced he is running for the Senate from the wonderful State of Utah. He will make a great Senator and worthy successor to Orrin Hatch, and has my full support and endorsement!!" Trump tweeted.

Romney, the Republican Party's nominee for President of the US in the 2012 election, has been an active critic of Trump since the 2016 presidential campaign, when he labelled the then Republican presidential candidate "a fraud".

However, following Trump's victory, Romney was considered a possible candidate for his secretary of state.

Romney responded later on Monday night, tweeting: "Thank you Mr. President for the support. I hope that over the course of the campaign I also earn the support and endorsement of the people of Utah," CNN reported.

The former Massachusetts governor announced on February 16 that he would run for the Senate seat.

In his announcement, Romney made a veiled critique of the President's tone on immigration.

"Utah welcomes legal immigrants from around the world -- Washington sends immigrants a message of exclusion," Romney said in a video on February 16 without mentioning Trump by name.