Adds quotes in paragraphs 2, background in paragraph 3

MADRID, Feb 17 (Reuters) - The Spanish government has ordered prosecutors to investigate social media platforms X, Meta META.O and TikTok for allegedly spreading AI-generated child sexual abuse material, Prime Minister Pedro Sanchez said on Tuesday.

"These platforms are undermining the mental health, dignity, and rights of our children," he wrote on his X account. "The state cannot allow this. The impunity of these giants must end."

Earlier this month, Sanchez announced several measures aimed at curbing online abuse and protecting children, including a proposed ban on access to social media platforms for those under the age of 16.