WASHINGTON (AFP) - A historic speech by Pope Francis to the US Congress on Sept 24 will be beamed live on giant screens outside the Capitol in a rare move, it was announced on Wednesday.

"In addition, Pope Francis has expressed an interest in making a brief appearance on the West Front (of the Capitol)," House Speaker John Boehner said in a statement.

Ticketing, access issues and other details will be announced later, he added.

Francis, expected to bring his message of peace and compassion to Washington, will become the first pope to address a joint meeting of the US Senate and the House of Representatives.

The format is normally reserved for heads of state of American allies. This year, Afghan President Ashraf Ghani, Israel's Benjamin Netanyahu and Japanese Prime Minister Shinzo Abe have had the honour.

Such dignitaries usually have no interaction with the public during their trip to the Capitol.

But this time Boehner - who is Catholic, as are nearly one third of members of Congress - intends to create a populist event out of the pope's appearance.

"The visit of Pope Francis to the US Capitol is a historic moment for the country," Boehner said.

An appearance by Francis at the West Front would be particularly rare. The Capitol's west side overlooks the vast National Mall and is the scene every four years of the presidential inauguration ceremony.

Pope Francis arrives for his first US visit on Sept 22 and is scheduled to meet President Barack Obama on the 23rd, a day before his Congress address.

On the 25th, the Pope visits the United Nations and leads a multi-faith event at New York's "Ground Zero" site to commemorate the victims of the 9/11 attacks.

He attends a global meeting of Catholic families in Philadelphia on Sept 26-27.

Prior to setting foot on US shores, Francis will visit Cuba from Sept 19.