In 2018, Francis revised the Catholic Church's official position on capital punishment, declaring the death penalty "inadmissible" in all circumstances.

"Consequently the church teaches, in the light of the Gospel, that the death penalty is inadmissible because it is an attack on the inviolability and dignity of the person," the revised Catechism states.

Before the change, Catholic teaching permitted the death penalty in cases where it was deemed the only effective means of protecting human life from a dangerous offender.

Earlier popes had maintained that exception, though Pope John Paul II increasingly advocated ending capital punishment, stressing that those convicted of crimes retain their human dignity.

Although Leo did not specifically mention the U.S. government's plans in his statement, his post comes after the Pentagon announced on Thursday that it had scheduled a firing squad execution for a man convicted of a mass shooting at a military base.

"Public executions are what oppressive dictatorships like Iran and Afghanistan do," Sen. Thom Tillis, R-N.C., said on Thursday. "It should not be happening in America."

Cardinal Pietro Parolin, the Vatican secretary of state, criticized the proposed broadcast, calling it "truly incomprehensible" and warning that it was "unacceptable to turn death into a spectacle."

"The Church’s position is one of total opposition to the death penalty; it is incompatible with human dignity and serves as no deterrent," Parolin told reporters on Friday. "It is truly incomprehensible that anyone would want to use this system today — I don’t know for what purpose. It is certainly unacceptable to turn death into a spectacle; even if the person is guilty, of course, there are other methods."

He added that the death penalty "is incompatible with human dignity and does not serve as a deterrent."

The head of the U.S. bishops conference, Archbishop Paul Coakley, expressed "shock" and "great sorrow" about the public execution plan and urged the U.S. to reconsider.

"In no way can Hasan’s actions be condoned but this decision is a barbaric promotion of a culture of death and must be reconsidered," he said in a statement on Friday. "The public execution even of one who has done grave harm will only further undermine the moral fabric of our nation and be a blight on the conscience of its people."

Leo's statement also did not mention the botched lethal injection of Christa Gail Pike in Tennessee. Pike survived the attempted execution despite two doses of pentobarbital being administered late last month.

The Associated Press and Reuters contributed to this report.