Former presidential candidate John Kerry has delivered a lecture at the University of Ulster's Magee campus in Londonderry on 21st century security.
Senator John Kerry delivered the Tip O'Neill lecture
He was invited to give the Tip O'Neill lecture by ex-SDLP leader John Hume.
The lecture has previously been given by prominent figures like Kofi Annan, Bill Clinton and Romano Prodi.
Mr Kerry said the west's long-term security was "dependent on addressing the multi-layered fabric of life which motivates those who use terror".
The Democrat senator for Massachusetts added: "The truth is that we are caught in the middle of a decades-old internal struggle in the Islamic world."
"It is fundamentally a war within Islam for the heart and soul of Islam, stretching from Morocco east to Indonesia.
"In regions where the mosque remains the only respected alternative to autocratic state structures, there is no credible secular alternative.
"And no centre of moral authority has emerged to stop those who would murder in the name of Islam."
Mr Kerry said success in the war on terror depended on the west having a strategy to increase the internal demand for transformation in the Middle East.
He said the case of Northern Ireland was an example of how to overcome a turbulent history and emerge into relative peace and stability.
"History is replete with examples of conflicts that at times seemed endless and intractable. But history also teaches us that if the desire for peace stays strong, it is always possible to prevail.
"There are lessons of perseverance and determination for peace to be learned from your experience here in Northern Ireland. You know better than anyone how long and arduous this process can be.
"The citizens of Northern Ireland have proven that progress is possible for those with the courage to seize it."
Mr Kerry said Iran was the "world's leading state sponsor of terrorism", which had defied the world by moving forward with its nuclear programme.
"A nuclear armed Iran clearly poses an unacceptable threat to global security," he added.
"To make sure this never happens, America must lead an unrelenting collective effort that matches the urgency of the threat."
Mr Kerry is an influential Democrat member of the US Senate Foreign Relations Committee and an advocate of non-proliferation controls.
During his election campaign in 2004, Senator Kerry accused the Bush administration of pushing the Northern Ireland peace process down the foreign policy agenda.
In a statement in February 2004, he called on the IRA and loyalists to disarm.
However, he also angered Ian Paisley's Democratic Unionist Party by insisting they "should not be allowed to disenfranchise half the population of Northern Ireland by refusing to form a government with Sinn Fein".
The Tip O'Neill Chair, financed by the Ireland Funds, commemorates the former speaker of the US House of Representatives, who was well known for his support of the peace process in Northern Ireland.