Prime Minister Benjamin Netanyahu of Israel held a diagram as he spoke about Iran’s nuclear program at the General Assembly on Thursday.

Mr. Netanyahu also thanked President Obama for his speech at the United Nations two days earlier in which he warned that he would not tolerate a nuclear-armed Iran. The Israeli leader’s speech emphasized Israel’s solidarity with the United States and appeared to be an attempt to smooth over differences over the urgency of what both view as the Iranian nuclear threat.

Mr. Netanyahu’s speech at the annual United Nations General Assembly was largely devoted to what he described as the existential threat posed by a nuclear-armed Iran, which he equated to a nuclear-armed Al Qaeda.

Mr. Netanyahu even held up a diagram of a cartoonish-looking bomb with a fuse to show the Israeli view of Iran’s progress in achieving the capability to make a nuclear weapon. He drew a red line through the level at which Iran would have amassed enough enriched uranium to make a bomb — which he said would be in the spring or summer of 2013.

“The relevant question is not when Iran will get the bomb,” he said. “It is at what stage can we stop Iran from getting the bomb.”

Iran has consistently denied it is seeking a nuclear weapon and has insisted its uranium enrichment program is meant for peaceful purposes.

Mr. Netanyahu also used his speech as a rejoinder to the Palestinian president, Mahmoud Abbas, who earlier had harshly denounced Israel from the General Assembly podium with a litany of grievances, including attacks by settlers and Israeli land policies in the occupied territories.

Mr. Abbas said he believed that Israel intended to destroy the basis for a two-state solution to the Israel-Palestinian conflict. He also received widespread applause in declaring that “there is no homeland for us except Palestine, and there is no land for us but Palestine.”

In response, Mr. Netanyahu said, “We won’t solve our conflict with libelous speeches at the United Nations.”