Alicia Keys has called on her fans to join in a protest campaigning against a New York newspaper's online classified pages, amid allegations the listings allow the facilitation of sex trafficking.

The Empire State of Mind singer has thrown her support behind officials at the Coalition Against Trafficking in Women (Catw), who are planning to gather outside the Manhattan headquarters of the Village Voice publication on Wednesday (16Nov11) and call on website editors to block sex advertisements on Backpage.com, which reportedly promote prostitution.

In a post on her Twitter.com page, Key writes, "What if these were your daughters? So Crazy! Please stand up with Catw against sex trafficking on Nov 16 in Nyc".

It's not the first time Village Voice has been targeted by a celebrity - in June (11) Ashton Kutcher took aim at the newspaper's editors, accusing them of "facilitating the sale of human beings" by publishing advertisements for escorts.

In a series of posts on Twitter.com, Kutcher, who runs a foundation to tackle human trafficking, wrote, "Hey Village Voice... maybe you can help me... How much $ (money) did your 'escorts' in you (sic) classifieds on Backpage make last year?

"How many of your girls selling themselves in your classifieds are you doing age verification on?"