Pope Francis has said abortion is a "murder", even shortly after conception.
However, he appeared to criticize some of the bishops of the Catholic Church in the United States for addressing US President Joe Biden's stance on supporting the idea of a political abortion instead of an apostolic method.
Pope Francis made the remarks on a plane trip from Slovakia on Wednesday.
Commenting on the US bishops' debate on whether President Biden, a Catholic, should be denied access to Communion, because he supports women's right to choose abortion, even if he opposes it, Pope Francis said:
"I would never stop anyone from receiving Communion, but I never realized that I have someone in front of me as if you are describing him, that is the truth," he said, without elaborating.
"Communion is not a reward for people who are without sin ... Communion is a gift, the presence of Jesus and his church," said Pope Francis.
"Abortion is murder… Those who have abortions kill," he said.
"In the third week after a woman becomes pregnant, often even when the mother is unaware (that she is pregnant), all the organs of the body have already begun to grow. It is human life. Really !. And this human life should be respected. Obviously. absolutely, "he said.
"Scientifically, it's human life," said Pope Francis.
In June last year, the General Conference of Bishops of the Roman Catholic Church in the United States voted on a bill on the participation of Communists that could prevent politicians from participating in Communion, including President Biden.