Iranian President Hassan Rouhani has blamed the rise of violent extremism in the Middle East on the West's "strategic blunders".
Speaking at the United Nations General Assembly, Mr Rouhani said the solution for the crisis had to come from within the region.
He also accused "certain intelligence agencies" of funding groups such as Islamic State (IS) in Syria and Iraq.
World leaders are meeting at the UN in New York to discuss the threat of IS.
In a wide-ranging speech, Mr Rouhani said that terrorism was now a "global threat, from New York to Mosul, from Damascus to Baghdad, from the easternmost to the westernmost parts of the world, from al Qaeda to [Islamic State]."
"The interests of Western countries in our region are tied to their recognition of beliefs and the desire of the people for democratic governance in the region.
Our region expects that the Western world would once and for all place itself in the company of those true seekers of democracy, and, hence, soften the bitter memories of its support for dictators," he said.
Mr Rouhani also spoke of the ongoing negotiations over Iran's nuclear programme, saying that he was "hopeful" of reaching a final agreement in the time remaining.
However he warned that any delay in arriving at that agreement "only raises the costs," and that a deal was "in the best interest of everyone, especially that of the nations of the region."
Iran was committed to continuing its nuclear enrichment work under international law, he added.
Iran and countries representing the P5+1 group - Germany and the permanent members of the UN Security Council: the United States, Britain, China, France and Russia - are involved in the negotiations.
They are discussing the potential lifting of Western sanctions upon Iran in exchange for a scaling-back of its uranium enrichment programme.
Iran insists that its nuclear programme is for peaceful purposes.