The United Nations on Friday named the fictional superhero Wonder Woman as its new honorary ambassador for gender equality amid protests criticizing the character not a qualified spokesperson for women and girls.

Wonder Woman is an "icon" for her commitments to justice, peace and equality, and "this character will help us reach new audiences with essential messages of our empowerment and equality," said UN Under-Secretary-General for Communications and Public Information Cristina Gallach at a designation ceremony held here.

The designation is part of a campaign, in cooperation with DC Entertainment and Warner Bros., to raise awareness about gender equality, according to the UN.

The designation also came at the 75th birthday of this well-known American comic character. Lynda Carter, an actress who played Wonder Woman in 1970s TV series and Gal Gadot, who has taken on the role in a film to be released next year, attended the ceremony.

Also at the ceremony, some UN staff, male and female, turned their back to the stage, some with fists in the air to show protests in silence.

An online petition started by UN staff before the designation said that Wonder Woman is no better than a real life female role model that women and girls can look up to, and besides this, the character has an "overtly sexualized image."

UN Spokesperson Stephane Dujarric, in response to questions, said that Wonder Woman portrays an image of female empowerment of strength and freedom, and that the UN is trying to reach different audiences that may not hear about UN goals with this image.

He also said in order to promote the UN goals including gender equality, the organization needs to partner with the civil society, the private sector, and sometimes with entertainment companies when it comes to mass communication.