Leading Roman Catholic church officials are strongly condemning human cloning, following the announcement Sunday by a U.S. company that it has cloned a human embryo for the first time. Church officials are calling it "an attack on human life."

Some of Pope John Paul II's closest advisers expressed serious concern at the announcement made by the American company, Advanced Cell Technology, that it has successfully cloned a human embryo.

The company maintains that the experiment is aimed at paving the way for medical therapies, not the cloning of human beings.

But Catholic Church leaders strongly condemned human cloning and related scientific experiments, saying they "could open dangerous paths and attack human life."

Upon hearing the news, Cardinal Ersilio Tonini called the human cloning technique "unacceptable." "We are facing the defeat of human thought," he said, urging the Italian parliament to approve legislation as quickly as possible to ban such experimentation in Italy.

Cardinal Tonini said, "Man can decide over everything except over another human being." He recalled how the European Parliament declared that human embryos must not be destroyed for therapeutic reasons or in favor of future generations.

The Cardinal added that the matter is "very serious" and "inadmissible," and that President Bush has said he is opposed to human cloning.

Catholic Archbishop Tarcisio Bertone said that "if it is true that it is a first step towards human cloning, then the initiative must be condemned." The bishop of Civitavecchia, Girolamo Grillo, called it "a sign of a crazed humanity."

The Vatican's top health official, Monsignor Javier Lozano Barragan, refused to be drawn into the cloning debate in too much detail, saying he had too little information.

"One needs to be cautious. Every discovery must be first published officially by the international scientific community," he said. But Monsignor Barragan noted that the Catholic Church "is always against everything that can undermine the natural conception of human life."