Iranian President Hassan Rouhani blamed the rise of violent extremism on "certain states" and on unidentified "intelligence agencies" and said it was up to the region to find a solution to the problem.
"Certain intelligence agencies have put blades in the hand of madmen, who now spare no one," Rouhani told the United Nations General Assembly on Thursday.
"The right solution to this quandary comes from within the region and regionally provided solution with international support and not from outside the region," he said.
The Iranian president lamented the situation in the Middle East – "a region of the world whose many parts are currently burning in the fire of extremism and radicalism," saying his neighboring countries, both "to the East and West," have resorted to violence and blood shed.
The fighters, who come to the region from across the world, have given rise to Islamophobia, ultimately leading to intervention of foreign forces in our region” While they do not speak a single language or have a single nationality, they conform to a single ideology, one of “violence and extremism.”
The goal of the extremists tearing through the Middle East is to destroy civilization.
Rouhani said that terrorism has become globalized, "from New York to Mosul, from Damascus to Baghdad...from al-Qaida to Islamic State."
On the hot-button nuclear issue, the president clarified that the "will of our people" put negotiations with Western powers back on the agenda, and not sanctions and threats.
The nuclear issue can only be resolved through negotiation, Rouhani averred, adding that those who think otherwise are "committing a grave mistake."
"No one should doubt that compromise and agreement on this issue is in the best interest of everyone especially that of the nations of the region," he said.
He said that both Iran and the 5+1 world powers have shown seriousness and optimism over the course of the past year and that the Islamic Republic of Iran has carried out its commitments in good faith.
He said Iran would remain committed to its "peaceful nuclear program, including enrichment," within the scope of international law.
In order for talks to succeed, excessive demands would have to be eliminated. An agreement with Iran on this topic could send a message to the world: "conflict resolution can happen through negotiation and respect" rather than sanction and conflict.
Earlier on Wednesday, Rouhani sat down for an exclusive interview with Charlie Rose on Wednesday (September 24) in which the leader touched on a range of pressing issues out of the Middle East including IS, Iran's relations with the United States and Saudi Arabia, the Iran nuclear talks and Western sanctions against Tehran.
On Islamic State, Rouhani called the militant extremists "savage and barbaric" but appeared to question the legality of the airstrikes in Syria, saying "if the air bombardment campaign is not within the framework of international law, it is to be condemned".
Speaking in New York on Tuesday Rouhani said that without a UN mandate or a request from the Assad government, military strikes had no legal standing. Rouhani, however, neither condemned nor endorsed the action.
"The way to combat terrorism, sir, is not for us to give birth to another terrorist group in order to stand up against an existing terrorist group," Rouhani told Rose. "These are the series of mistakes that have composed the rings of the chain that have taken us from where we were to where we are today," Rouhani said.
The interview took place the same day British Prime Minister David Cameron's office said he and Rouhani agreed the two countries should work to improve ties, and that it was crucial for Tehran and major powers to reach a long-term nuclear deal.
Addressing the UN General Assembly, Cameron said Iran "should be given a chance to show it can be part of the solution"
The Prime Minister and President met at the United Nations in New York in the first such meeting since the Iranian Revolution in 1979.
Speaking with Rose, Rouhani said he would not meet the US president.
"Today conditions do not dictate such a meeting" between himself and US President Barack Obama, adding however that he believed relations between Iran and the United States would eventually improve.
"One day, these distances will be shortened. The two nations, the two people will not allow such gaps to exist in perpetuity. But how to decrease these gaps, to resolve the issues and the difficulties?" Rouhani said
Senior foreign ministry officials from the United States, Britain, China, France, Germany, Russia and Iran are meeting this week in New York. Officials close to the talks say a nuclear deal is unlikely in coming days given deep disagreement on issues such as the scope of Iran's future enrichment program.