(CNN) -- Israeli Prime Minister Benjamin Netanyahu exhorted the United Nations General Assembly on Thursday to draw "a clear red line" to stop Iran from developing nuclear weapons.
In a theatrical gesture, Netanyahu held up a cartoon-like drawing of a spherical bomb and drew a red line below the fuse, "before Iran completes the second stage of nuclear enrichment to make a bomb," he said.
"It's not a question of whether Iran will get the bomb. The question is at what stage can we stop Iran from getting the bomb," said Netanyahu, who also accused Iran of aggression.
"I ask, given this record of Iranian aggression without nuclear weapons, just imagine Iranian aggression with nuclear weapons," the Israeli prime minister said. "Who among you would feel safe in the Middle East? Who would be safe in Europe? Who would be safe in America? Who would be safe anywhere?"
But Iran's ambassador to the United Nations, Eshagh al-Habib, called Netanyahu's remarks "entirely baseless."
"I do not dignify it with an answer other than categorically rejecting it, in particular regarding the nuclear program of my country which is exclusively peaceful and in full conformity with our international obligations and in exercising our inalienable right to use nuclear science and technology for peaceful purposes," he said in a statement.
He went on to say that Israel is a nation "based on terrorism."
Iranian President Mahmoud Ahmadinejad told CNN that his country won't be influenced by a threat from Israel and a demand from U.S. President Barack Obama to abandon plans to acquire nuclear weapons.
"When we say we do not take it seriously, we mean that it impacts -- it does not impact our policies in the slightest," Ahmadinejad told CNN's Fareed Zakaria in an interview to be aired Sunday at 10 a.m. and 1 p.m. Eastern.
The White House highlighted how Obama sided with Israel in his speech before the General Assembly this week.
"As the prime minister said, the United States and Israel share the goal of preventing Iran from acquiring a nuclear weapon," National Security Council spokesman Tommy Vietor said.
U.S. Secretary of State Hillary Clinton met with Netanyahu for more than an hour later Thursday, a senior State Department official said.
Clinton and Netanyahu talked at length about Iran and agreed to continue "close consultation and cooperation toward achieving" the goal of stopping Iran from getting atomic weapons, the official said.
Speeches by Netanyahu and Palestinian Authority President Mahmoud Abbas drew the most attention at the United Nations on Thursday.
Abbas said Palestinians will continue to seek full membership status in the United Nations, but they have begun "intensive consultations" with member states about having the Palestinian Authority become a nonmember state, one step up from its current status as a permanent observer.
"We are confident that the vast majority of the countries of the world support our endeavor aimed at salvaging the chances for a just peace," Abbas said. "In our endeavor, we do not seek to delegitimize an existing state -- that is Israel -- but rather to assert the state that must be realized -- that is Palestine."
Then, departing from his prepared speech, Abbas added, to applause: "We are not attempting to delegitimize them, they are trying to delegitimize us."
Speaking later, Netanyahu criticized Abbas' remarks.
"We won't solve our conflict with libelous speeches at the U.N. That's not the way to solve them. We won't solve our differences with a unilateral declaration of statehood," Israel's leader said. "We have to sit together and negotiate together in which a demilitarized Palestinian state recognizes the one and only Jewish state."
Last year, the Palestinian Authority failed in its bid to win U.N. recognition as an independent state.
In their latest initiative to seek non-member observer status, the Palestinians are likely to submit a new resolution after the November 6 U.S. presidential election in an effort to prevent the issue from becoming political fodder. Palestinian officials have expressed concern about pessimistic comments by Republican presidential nominee Mitt Romney about the chances for peace in the region.
In his speech Thursday, Abbas criticized Israel and said Palestinians were facing "a campaign of ethnic cleansing" in which they are being denied full access to houses of worship, schools, hospitals and housing.
"The occupying power is also continuing its construction and expansion of settlements in different areas throughout the West Bank," he told the assembly.
Israel rejects a Palestinian state and refuses to end its occupation, Abbas said.
"I speak on behalf of an angry people," he said. "Israel continues to enjoy impunity."
For Israel, the issue of how to respond to Iran's nuclear program has put a strain on relations between Netanyahu and Obama. Tehran insists its nuclear program is for peaceful purposes, but Western leaders say they believe it is aimed at building a weapon.
Netanyahu has been pushing the United States to establish a clear "red line" that Iran cannot cross if it wants to avoid war.
Israel seeks international urgency, as negotiations aimed at curbing Iran's nuclear ambitions have failed to produce an agreement and the effectiveness of sanctions on Tehran remains unclear.
Later Thursday, Chinese Foreign Minister Yang Jiechi raised another contentious international issue during his speech to the assembly -- that of the heated territorial dispute between China and Japan over a set of islands in the East China Sea.
Yang accused Japan, a key U.S. ally, of stealing the remote islands from China in the past and warned that Beijing would be "firm" in upholding its territorial sovereignty.
The Japanese government's announcement this month of the acquisition of several of the disputed islands from a Japanese family has heightened tensions between the two countries.
Violent anti-Japanese protests have taken place in Chinese cities, and economic ties between Asia's two largest economies have started to sour. Meanwhile, patrol vessels from the two countries have been frequently locked in tense standoffs in the waters around the islands after China sent a flotilla of ships to the area.
Prime Minister Yoshihiko Noda of Japan referred indirectly to the situation in his speech to the assembly Wednesday. Noda emphasized Tokyo's commitment to using international law to resolve territorial disputes and called for greater adherence to the "rule of law" by other nations.
CNN's Jethro Mullen and Christine Theodorou contributed to this report.