A rare handwritten poem signed by Anne Frank has sold at auction for 140,000 euro (£120,000).

In a sign of the enduring popularity of the Jewish diarist who became a symbol for Holocaust victims, the sale price, which does not include the auctioneer's commission, was nearly three times the upper limit of the Dutch auction house's pre-sale estimate.

The eight-line poem, half of which was copied from a Dutch book of verse, is dated March 28 1942, shortly before Anne and her family went into hiding from wartime Nazi occupiers in a secret apartment in an Amsterdam canal house.

It was sold to an online bidder, whose identity was not released.

The poem was accompanied by a letter of authenticity from the seller, Anne's former school friend, Jacqueline van Maarsen. The poem is addressed to her late sister, Christiane.

Ms van Maarsen also has a poem written by Anne that was addressed to her.

"I know that my sister was not as attached to this verse from Anne to her as I am to the verse Anne addressed to me, and that is the reason that I am now putting it up for sale," she said in a letter accompanying the poem.

Auction house Bubb Kuyper put a pre-sale estimate of between 30,000 and 50,000 euro (£25,000 to £42,000) on the poem.

Anne Frank Foundation spokeswoman Maatje Mostart said there is no doubt about the poem's authenticity.

"Jacqueline was an important person for Anne," Ms Mostart said.

Ms Mostart said it is "very special" for a piece of Anne's handwriting to come up for auction, but added that the foundation did not plan to bid for the poem.

Anne and her family were betrayed and captured late in the war and deported. Anne died in the Bergen-Belsen Nazi concentration camp aged 15, shortly before it was liberated by Allied forces.

Her father survived the war and published her diary, which went on to become a global best-seller.