In a Twitter post, Rasmussen, who was Danish premier from 2009-2011 and 2015-2019, tagged Trump and said he had “just a little piece of advice”.

“This is the right way to leave office with honor once you have lost election,” Rasmussen continued, posting a photograph of himself walking away from the Danish parliament in Copenhagen with a rucksack over his shoulder.

“Thanks for honest conversations over the last 4 years. Let's keep in touch. Best regards. Lars Løkke Rasmussen, former Prime Minister of Denmark,” the former PM concluded.

Trump propagated disinformation about voter fraud prior to the US election and, since Tuesday’s vote, has falsely claimed victory and filed lawsuits in a number of states, before last night making a televised speech so crammed with falsehoods that many news stations cut their broadcasts and even some Republicans condemned it as undermining democracy.

A winner of the US general election is yet to be declared, but vote counting across battleground states shows Democrat Joe Biden steadily closing in on victory.

It’s not the first time Rasmussen, whose time as leader of the Danish government overlapped with Trump’s first two years as president, has challenged the belligerent US commander-in-chief, on social media and elsewhere.

In February 2018, he tweeted Trump to ask for reform on gun control in the wake of a shooting at Marjory Stoneman Douglas High School in Parkland, Florida, where 17 people were killed.

He subsequently admitted that his tweet had not set “a new standard for diplomacy”.

READ ALSO: OPINION: Why PM Lars Løkke Rasmussen's error-strewn English is fine by us (2018)

He also made public remarks criticising Trump’s withdrawal from the Paris climate accord and to censure the president over American tariffs on metal imported into the United States, and called his 2018 speech at the United Nations general assembly “discouraging”.

Rasmussen said prior to meeting Trump for the first time in 2017 that “first and foremost I want to have a good meeting” in “a good atmosphere that will allow me to keep in touch with the American president”.

If his latest social media message to the president is anything to go by, the former prime minister’s feelings haven’t changed in that regard.

READ ALSO: How are Americans in Denmark reacting to the US election?