The Iranian leader also said in a wide-ranging Associated Press interview Tuesday that he expects "free and open" discussion of nuclear issues at a meeting next week with six world powers, but stressed that his country would not negotiate on its own nuclear plans.
He sought to open a wider nuclear dialogue with the West, and said the onus should be on the United States and other major nuclear powers to give up their weapons and to expand opportunities for all countries to make peaceful use of nuclear power.
Speaking to AP reporters and editors just hours after arriving in the United States, Ahmadinejad said he will seek a quick resolution to the case of three American hikers jailed in Iran.
He dismissed last week's U.S. shift away from a planned long-range missile shield in Europe, meant to guard against an Iranian strike, as "a respectful way of buying out" Russian objections.
"I heard Mr. Obama saying the next threat is Iran. Iran is an opportunity for everyone," Ahmadinejad said.
The Iranian leader said Obama is not the first U.S. president to believe Iran is a threat and said the president should read up on history "to see what the fate is of viewing these problems from this perspective."
"Historically, whoever made friends with Iran saw a lot of opportunities," Ahmadinejad said.
The Iranian president's remarks on those and other issues in an hour-long interview at his New York hotel appeared designed to present his country as open to a broad international dialogue and to soften Iran's image as a rogue nation bent on spreading its Islamic revolution.
Ahmadinejad is in New York to address the United Nations General Assembly on Wednesday. Obama is also speaking Wednesday.
Ahmadinejad remained soft-spoken and almost completely still in his chair as he politely fielded questions on a wide range of controversies rankling Iran's relationship with the West. He would occasionally nod or offer a small smile, particularly when he appeared pleased with a point he had made, but the Iranian leader never gestured or raised his voice. A few questions prompted an animated flurry of conversation in Farsi among members of his delegation before he gave a response that was translated into English.
He reiterated explicitly that Iran is not building nuclear weapons.
"I hope that Mr. Obama will move in the direction of change," Ahmadinejad said. At another point he said, "The sources of insecurity around the world need to be discussed."
The United States, Israel and the European Union fear that Iran is using its nuclear program to covertly develop nuclear weapons. But Tehran says the program serves purely civilian purposes and asserts its right to enrich uranium for use in nuclear power plants to generate electricity.
The U.S. has agreed for the first time to fully join European-led talks with Iran, fulfilling an Obama campaign pledge to engage adversaries but risking a gambit that Iran will hijack the talks and yield nothing.
The Bush administration had refused to negotiate further with Iran until it agreed to freeze its uranium enrichment efforts, which it has refused to do.
When asked about the three American hikers, Ahmadinejad said they broke the law by illegally entering Iran. Nevertheless, Ahmadinejad said he will ask the Iranian judiciary to treat the case with "maximum lenience."
The Iranian leader did not elaborate on what that might mean for the fate of the three Americans. Families of the imprisoned hikers have said they hope Ahmadinejad's visit to New York might yield a breakthrough in the case.
The three have been held for 53 days since they went off course while hiking in northern Iraq's Kurdistan region in July. Their case has become the latest source of friction between the U.S. and Iran.
Ahmadinejad also was asked about the case of an Iranian-Canadian journalist, Maziar Bahari, who was working for Newsweek magazine and imprisoned while covering the social unrest in Iran after the disputed June presidential election. Ahmadinejad did not reply about Bahari, limiting his remarks to the case of the hikers.
The ambassador at Iran's mission at the United Nations, Mohammad Khazee, said later that he hoped the case of Bahari would also be resolved.
Ahmadinejad said he regrets the deaths of protesters in the violence that followed his country's disputed presidential elections, but denied that his government had any role in the killings.
Ahmadinejad said those who died were "not at fault." He instead said the responsibility lies with Iranian opposition politicians and with "European and American politicians" who he said fueled the violence.
"We believe what they did was very wrong," he said.
Iran's pro-reform opposition has staged dramatic protests, claiming that Ahmadinejad's victory in the June voting was fraudulent. The Iranian government waged a bloody crackdown and opposition groups say at least 72 protesters were killed. Government officials maintain that only 36 people died, and Ahmadinejad repeated that claim.
"It is all very regrettable," Ahmadinejad said, adding that he has directed Iran's judicial system to investigate each death. "The government has no role in these events."
Ahmadinejad muted his remarks on the Holocaust, an event he has frequently questioned as a matter of historical fact. As recently as last Friday, Ahmadinejad questioned whether the Holocaust was "a real event" and said it was used by Jews to trick the West into backing the creation of Israel. In a speech in Tehran, he said the Jewish state was created out of "a lie and a mythical claim."
In a lengthy exchange on Tuesday, he did not repeat those outright denials.
Using markedly less confrontational language than he has in the past, Ahmadinejad said he is not interested in debating historical details. Instead, he said he wants to focus on what he calls the wrong done to Palestinians who lost their land when the state of Israel was formed.
Ahmadinejad said the Holocaust is used as a pretext for the repression of Palestinians. He grouped the deaths of Jews during World War II with those of millions of others who died.
Israeli Prime Minister Benjamin Netanyahu planned to boycott the Iranian's address.
Ahmadinejad repeated his nation's interest in cooperating to help stabilize Afghanistan and help Iraq, but blamed the United States for having created chaos in the war-torn country on Iran's eastern border.
"The occupying forces or the groups that have sent in the military to these two states, if indeed their policy has led to further instability, what do they want us to do?" Ahmadinejad said. "What exactly can we do for a car that has decided to speed up and basically crash down the hill? I don't see exactly what we can do under that scenario."
AP White House Correspondent Jennifer Loven contributed to this report.