Pope Francis has appealed to the U.S. Congress to embrace peace through diplomatic means, to stop the widespread and lethal global arms trade and to find ways to "end the many armed conflicts throughout the world."

"Why are deadly weapons being sold to those who plan to inflict untold suffering on individuals and society?" the Pope who is now often viewed as much a world leader as a church leader, asked.

"Sadly, the answer, as we all know, is simply for money, money that is drenched in blood, often innocent blood. In the face of this shameful and culpable silence, it is our duty to confront the problem and to stop the arms trade," said Francis.

It was the first address to the U.S. legislators by the head of the Catholic Church and came the day before the pontiff was to address the U.N. General Assembly and after he had spoken before President Barack Obama at the Whitehouse.

The three-day U.S. Sustainable Development Summit starts Sept. 25 with a record number of top world leaders expected to attend, as well as heads of multilateral bodies like the World Bank and the International Monetary Fund.

Pope Francis will make a historic address to the U.N. General Assembly at the global gathering where U.N.Secretary-General Ban Ki-moon hopes his presence will spur action from world leaders on climate change.

The three-day U.N. Sustainable Development Summit starts Sept. 25 with a record number of top world leaders expected to attend, as well as heads of multilateral bodies like the World Bank and the International Monetary Fund.

There they will address global crises that they stubbornly disagree on, including climate change, the war in Syria, and a historic exodus of people fleeing conflict and hunger,.

In his Washington address, the Pope also noted that religious extremism can play an evil role in the persecution of the powerless and fighting it needs constant vigilance between religious freedoms and responsibilities.

"Our world is increasingly a place of violent conflict, hatred and brutal atrocities, committed even in the name of God and religion. We know that no religion is immune from forms of individual delusion or ideological extremism.

"This means that we must be especially attentive to every type of fundamentalism, whether religious or of any other kind.

"A delicate balance is required to combat violence perpetrated in the name of religion, an ideology or an economic system, while also safeguarding religious freedom, intellectual freedom and individual freedoms," he said to an audience that applauded him but had in it many supporters of international arms trading.