The former president of Iran has stressed that the world's three dominant faiths must work together in harmony to bring peace to a violent world during a speech at the Washington National Cathedral earlier in the month.

"It's good at the present time, where war, violence and repression is so prevalent across the world, for all of us who are followers of God's religion to pursue all efforts for the establishment of peace and security," former president of Iran Mohammad Khatami told the 1,300-strong congregation gathered to hear him speak.

The invitation of the former Iranian president has sparked controversy, however, due to the suppression of religion in the country during his reign.

Canon John L Peterson, Washington Cathedral's international programmes, defended the invitation in a letter to The Church of England Newspaper, insisting that it was controversial but necessary to foster peaceful relations, Religious Intelligence reported.

"Although former president Khatami is viewed negatively by some, he is important as the most moderate Iranian voice willing to discourse with Americans on matters of peace among the Abrahamic faiths," Canon Peterson said.

Canon Peterson pointed to meetings between Khatami and former US President Jimmy Carter and UN Secretary General Kofi Annan as "indications of the acceptance for and importance of discussions with the former Iranian leader". Khatami even travelled to Rome to meet with Pope John Paul II in 1999.

"Our invitation is a gesture of peaceful outreach for dialogue and listening that we hope will lead our world closer toward reconciliation," Canon Peterson said.

However the chairman and vice-chairman of the United States Commission on International Religious Freedom questioned the propriety of the visit, writing in the Washington Post there was a "troubling irony" in the Cathedral's invitation.

"In his own country, Khatami held office as president from 1997 to 2005 while religious minorities - including Jews, Christians, Sunni and Sufi Muslims, Baha'is, dissident Shiite Muslims and Zoroastrians - faced systematic harassment, discrimination, imprisonment, torture and even execution because of their religious beliefs," they stated.

The Commission leaders argued further that his call for harmony among the "Abrahamic Faiths" came in stark contrast to his actions while in power and that the Cathedral's decision to host Khatami was not only extraordinary but also jeopardised the National Cathedral's standing as "one of America's most significant moral symbols."

The Commission's views were echoed by three bishops of The Episcopal Church, who urged the Cathedral to cancel the invitation. The Bishops of Northern Indiana, Rhode Island and Southwest Florida released an open letter prior to the event in which they stated that Khatami's "actions do not support the goal of reconciliation for which our Church has so fervently prayed and worked."

The bishops added that Khatami's presence at the Cathedral harmed the Church's relationship with Judaism and highlights "our Church's blatant disregard of Iran's dismal human rights record and its failure to live as a responsible member of the community of nations."