John Lennon fans around the world are marking what would have been the ex-Beatle's 70th birthday.

Lennon was gunned down in New York almost 30 years ago and his widow Yoko Ono has said she is still getting over his death.

Ono, 77, has been in Iceland for the re-lighting of the Imagine Peace Tower, an installation she created in memory of one of the world's must influential songwriters.

She said: "It was very hard because it was a sudden thing that happened, he wasn't ill for a long time or anything, it's just, we were talking before that you know, and, it was very hard."

"I think I am getting over it in a kind of way, in my own unique way, but it's still lingering".

The event in Reykjavik was one of several organized around the world to mark the anniversary. Internet search site Google paid tribute to Lennon with a hand-drawn logo and mini-video based on his hit Imagine.

Ono added: "It's very interesting, you know, that songs like Gimme Some Truth mean a lot now, and of course Give Peace a Chance and Imagine. All his political songs really have a lot of meaning right now for people."

The Japanese-born artist believes Lennon, who became a symbol of the anti-Vietnam war movement, would still be politically active were he alive today, but that after his death it was up to her to carry on his message of peace.

She said: "We were partners and it was almost like we were in a battleground, really struggling you know, for peace, for world peace, against all odds.

"Many people didn't like us speaking out about war, and war and peace, and then suddenly he was gunned down so I had to continue as a partner."