Speaking at a news conference, Villegas read a statement strongly condemning the Spanish newspaper for publishing the image, saying the daily "violated journalistic ethics" and "created an international scandal."
Foreign Minister Elias Jaua said Thursday night in a telephone call broadcast on state television that the government instructed its ambassador in Spain, Bernardo Alvarez, to work with the attorney general in preparing the case.
The foreign minister said Vice President Nicolas Maduro instructed officials "to take actions leading to a lawsuit against that daily for the acts that seriously offended the president's dignity."
Pedro J. Ramirez, editor of the Spanish paper El Mundo, said in tweets on Thursday that his paper was also offered the photo. However, he and other editors expressed reservations over whether it was genuine before announcing a unanimous decision to refuse it.
Santiago Lyon, AP vice president and director of photography, said the AP turned down the agency's offer of exclusive rights to distribute the photo "because of serious concerns over medical privacy issues as well as the authenticity and provenance of the image."
Associated Press writers Jorge Rueda and Ian James in Caracas, Venezuela, and Jorge Sainz in Madrid contributed to this report.