"They're getting closer and closer to the bomb and they have to be told in no uncertain terms that that will not be allowed to happen," Netanyahu told the CBS News program "Face the Nation."
The Obama administration must show "by action" that "the military option which is on the table is truly on the table," Netanyahu said, adding if the White House moves too slowly in Israel's eyes, Israel will do what it must.
"You know, our clocks are ticking in a different pace," he said of Washington and Jerusalem.
"We're closer [to Iran] than the United States. We're more vulnerable. And therefore we'll have to address this question of how to stop Iran, perhaps before the United States does," he said.
"But as the prime minister of Israel, I'm determined to do whatever is necessary to defend my country, the one and only Jewish state, from a regime that threatens us with renewed annihilation."
Netanyahu told the United Nations in September Iran could amass enough enriched uranium to fuel a nuclear bomb by mid-2013.
He told "Face the Nation" Sunday last month's Iranian presidential elections didn't really change anything in Iran's nuclear ambitions, even if U.S. officials view Iranian President-elect Hassan Rouhani, an Islamic cleric, as a relative moderate.
U.S. officials are preparing to reach out to the incoming leader for direct talks on the Iranian nuclear program. Netanyahu said Washington should understand Rouhani is no more trustworthy than his predecessor, Mahmoud Ahmadinejad.
"His strategy is, be a wolf in sheep's clothing. Smile and build a bomb," Netanyahu said of Rouhani, who he said, by contrast, criticized Ahmadinejad "for being a wolf in wolf's clothing."
Rouhani, who was elected June 14 and takes office Aug. 3, says he is open to direct talks with Washington but maintains Iran will continue producing nuclear fuel in violation of U.N. Security Council resolutions.
Iran insists it is legally entitled to enrich uranium for peaceful purposes and denies it wants to become a nuclear weapons state.
Representatives of the six world powers known as the P5-plus-1 who are negotiating with Iran -- the United States, Russia, China, France, Britain and Germany -- are to meet in Brussels Tuesday to discuss strategy under a Rouhani regime.
Rouhani is a former nuclear negotiator.
Washington and other powers seem to show "no sense of urgency" about Iran's nuclear threat because they're focused on the Syrian civil war and the ouster of Egypt's leader, Netanyahu told CBS.
"And yet Iran is the most urgent matter of all," he said.
"All the problems that we have, however important, will be dwarfed by this messianic, apocalyptic, extreme regime that would have atomic bombs."