A 1954 letter written by Albert Einstein and known as the "God letter" because he discussed his thoughts about God and religion has fetched close to $2.9 million at an auction in New York.

The letter, which was sold at Christie's on Tuesday, was written the year before the Nobel prize-winning physicist's death. It was addressed to philosopher Eric Gutkind, who had written a book about Jewish spirituality and the pursuit of science.

In the letter, Einstein declared, "The word God is for me nothing more than the expression and product of human weaknesses, the Bible a collection of honorable but still primitive legends."

Einstein was constantly questioned about his religious beliefs during his lifetime.

The letter had previously sold for $404,000 at Bloomsbury Auctions in London in 2008.