Bob Dylan has released his first track in eight years -- a 17-minute song about the assassination of US President John F. Kennedy.

The 78-year-old singer-songwriter shared a link to the track, called "Murder Most Foul," on Twitter on Thursday night.

The song begins by recounting the murder of Kennedy, who was shot on November 22, 1963 while riding in an open limousine alongside his wife, Jackie, during a tour of Dallas, Texas.

"It was a dark day in Dallas, 1963, a day that will live on in infamy," it begins. "President Kennedy was a'riding high -- good day to be living and a good day to die."

Sharing the link on Twitter, Dylan wrote: "Greetings to my fans and followers with gratitude for all your support and loyalty across the years. This is an unreleased song we recorded a while back that you might find interesting. Stay safe, stay observant and may God be with you. Bob Dylan."

Dylan, whose most famous tracks include "The Times They Are a-Changin'," "Like a Rolling Stone" and "Mr. Tambourine Man," won the first of his 11 Grammy awards in 1973.

In 2008, he won a Pulitzer Prize special citation for "his profound impact on popular music and American culture, marked by lyrical compositions of extraordinary poetic power."

And in 2016, Dylan was awarded the Nobel Prize in Literature for "having created new poetic expressions within the great American song tradition."