The Beatles rocker was gunned down by crazed fan Mark Chapman outside his Manhattan home on 8 December 1980. He was just 40 when he died.

Yoko, 83, who married the Imagine singer in 1969, marked Thursday's (08Dec16) anniversary with a post on her Facebook that called the U.S. a "war zone" due to its lax controls on gun ownership.

"Dear Friends, Every day, 91 Americans are killed with guns," her message read. “We are turning this beautiful country into a War Zone. Together, let's bring back America, the green land of Peace. The death of a loved one is a hollowing experience."

Her missive was accompanied by a famous picture of John's bloodied glasses, above which were written the words, "Over 1,200,000 people have been killed by guns in the U.S.A. since John Lennon was shot and killed on December 8th 1980."

Yoko and John's son Sean, 41, also marked his father's death on social media by posting a picture of his parents in a loving pose.