US president Donald Trump might be known for his relentless tweeting, but it's his predecessor Barack Obama who has made Twitter history. 

A tweet by Obama obliquely referencing events in Virginia has received 2.9 million likes and counting, making it the most liked tweet ever. 

The tweet included a photo of Obama looking into a window with four little children and cited former South African president Nelson Mandela's words that "no one is born hating another person because of the colour of his skin or his background or his religion." 

Obama finished off the Mandela quote in two subsequent tweets, with the second adding "people must learn to hate, and if they can learn to hate, they can be taught to love..." and the third wrapping things up: "'...For love comes more naturally to the human heart than its opposite." - Nelson Mandela." 

The quotes come from Mandela's autobiography Long Walk to Freedom, while the photo was taken by Obama's White House photographer Peter D'Souza. 

Virginia has erupted into violence in recent days, with white nationalists and anti-fascists clashing and a man ramming a car into a crowd of left-wing protesters, killing a 32-year-old in the process. 

The second most-liked tweet ever now belongs to Ariana Grande, who had posted an emotional message last May after terrorists bombed a concert of hers in Manchester. That tweet garnered a shade over 2.7 million likes.