Mahmoud Ahmadinejad, president of Iran, takes a seat with his delegation during the 67th session of the United Nations General Assembly on Wednesday, September 26, in New York. The event gathers more than 100 heads of state and government for high-level meetings on nuclear safety, regional conflicts, health and nutrition, and environment issues. 
President of the Republic of Liberia Ellen Johnson-Sirleaf sits after addressing world leaders on Wednesday. 
French President Francois Hollande, left, and his Egyptian counterpart, Mohamed Morsy, talk during a bilateral meeting on Tuesday, September 25. 
Sheikh Hamad bin Khalifa Al Thani, emir of Qatar, arrives to address the U.N. General Assembly on Tuesday. 
Brazilian President Dilma Vana Rousseff delivers her address to the General Assembly on Tuesday. 
The president of Libya's parliament, Mohamed al-Magariaf, attends Tuesday's speeches. 
United Nations Secretary-General Ban Ki-moon, standing, makes a toast during a luncheon on Tuesday as U.S. Secretary of State Hillary Clinton, left, looks on. 
Indonesia's President Susilo Bambang Yudhoyono waits to address the General Assembly on Tuesday. 
U.S. President Barack Obama addresses the United Nations General Assembly on Tuesday, September 25, in New York. 
Obama speaks at the assembly on Tuesday. 
U.S. first lady Michelle Obama, center, listens to her husband speak on Tuesday. 
Afghan President Hamid Karzai attends Tuesday's speeches. 
U.N. General Secretary Ban Ki-moon, second left, arrives on Tuesday. 
Afghan President Hamid Karzai, center, arrives on Tuesday. 
Palestinian Authority President Mahmoud Abbas, center, arrives at the United Nations on Tuesday. 
- NEW: Ahmadinejad says world powers are seeking to intimidate Iran and other nations
- The U.S. delegation "has decided not to attend" Ahmadinejad's speech
- He stirred controversy at the session when he said Israel has "no roots" in the Middle East
- U.S. will do what's needed to stop Iran from getting nuclear arms, Obama said Tuesday
(CNN) -- Iranian President Mahmoud Ahmadinejad said his nation was committed to peace and accused world powers of double standards in pursuing an arms race, as he took to the stage Wednesday at the United Nations.
The address by the Iranian president on day two of the United Nations General Debate was widely expected to prove contentious, given his history of controversial statements.
Speaking from the assembly's iconic green marble podium Wednesday for the eighth and last time, Ahmadinejad told delegates that Iran has a "global vision and welcomes any effort intended to provide and promote peace, stability and tranquility" in the world.
However, an "arms race and intimidation by nuclear weapons and weapons of mass destruction by the hegemonic powers have become prevalent," he said, and Iran finds itself under threat from world powers seeking to impose their views.
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Iranian president: UNSEC has failed "Continued threat by the uncivilized Zionists to resort to military action against our great nation is a clear example of this bitter reality," he said.
"A state of mistrust has cast its shadow on the international relations, whilst there is no trusted or just authority to help resolve world conflicts."
The place set aside for the U.S. delegation was empty as Ahmadinejad spoke.
The U.S. delegation "decided not to attend" Ahmadinejad's speech, according to Erin Pelton, a spokeswoman for the U.S. Mission to the United Nations.
"Over the past couple of days, we've seen Mr. Ahmadinejad once again use his trip to the U.N. not to address the legitimate aspirations of the Iranian people, but to instead spout paranoid theories and repulsive slurs against Israel."
Ahmadinejad was widely expected to serve up a rebuttal to a series of sharp jabs from Western leaders Tuesday, who accused him of fostering instability in the region by way of Iran's nuclear program and support of embattled Syrian President Bashar al-Assad.
While Iranian leaders say their nuclear program is for peaceful purposes, Western leaders believe Tehran wants to build a nuclear weapon. U.N. inspectors also have expressed doubts about the program's aims.
Ahmadinejad told delegates that the United Nations should be restructured, noting that many pressing global issues are the result of mismanagement, and that "self-proclaimed centers of power ... have entrusted themselves to the devil."
The world is at a "historic juncture" now that Marxist systems are virtually gone and "capitalism is bogged down in a self-made quagmire," he said, which could allow for other nations to "play a more active role" in global decision making.
Ahmadinejad's speech was not as provocative as some had predicted. Nonetheless, as he spoke, there was a demonstration against Iran outside the United Nations, with former New York Mayor Rudy Giuliani among the speakers.
Earlier this week, the Iranian president stirred controversy at the session when he declared that Israel has "no roots" in the Middle East.
President Barack Obama, who's campaigning for re-election, blasted Ahmadinejad the following day, suggesting that Iran and Syria are on the losing end of a sweeping tide of democracy in the region.
The United States "will do what we must to prevent Iran from obtaining a nuclear weapon," Obama said, reminding other leaders in attendance that a "nuclear-armed Iran is not a challenge that can be contained."
World leaders this week have discussed a range of issues like poverty, global warming, women's empowerment and the prospect of renewed conflicts in sub-Saharan Africa, but the Syrian civil war and violence in the Middle East and North Africa are expected to continue to dominate the proceedings.
Before Ahmadinejad's speech, Yemeni President Abdu Rabu Mansour Hadi took the podium Wednesday, reaffirming his nation's commitment to the fight against Islamic militants. He offered to talk with extremist groups, including al Qaeda, provided they put down their weapons and repent.
Meanwhile, U.N. Secretary-General Ban Ki-moon sought to keep world attention focused on the worsening crisis in North Africa's Sahel region, which has been plagued by a deadly mix of drought, famine and Islamic militancy.
"The Sahel is at a critical juncture," he said Wednesday. "Political turmoil, extreme climatic conditions and fragile economies are combining to create a perfect storm of vulnerability."
"The people and governments of the region need urgent international support," he added.
