Israeli Prime Minister Benjamin Netanyahu's blistering attack on a U.S. push for a nuclear accord with Iran soured ties with Washington but could boost his prospects in elections this month, experts say.

Netanyahu, seeking re-election on March 17, infuriated the White House with his address Tuesday to U.S. Congress, where he laid out Israeli concerns at an emerging world deal with Iran on its nuclear program.

The United States said Wednesday tough challenges remained to seal a nuclear deal with Iran, vowing not to be distracted by external politics in its quest to stop Tehran acquiring the atomic bomb.

Secretary of State John Kerry and his Iranian counterpart Mohammad Javad Zarif wrapped up three days of "intense" nuclear negotiations in the Swiss lakeside town of Montreux with still no deal, as a March 31 deadline for a framework agreement looms.

Israeli Prime Minister Benjamin Netanyahu on Wednesday brushed aside criticism from U.S. President Barack Obama of his speech to Congress, in which he warned Washington was paving the way to a nuclear-armed Iran.

The White House was infuriated by Netanyahu's address Tuesday to a joint session of the U.S. Congress, where he laid out Israeli concerns at an emerging world deal with Iran on its nuclear program.

Prime Minister Benjamin Netanyahu's impassioned speech Tuesday in the U.S. Congress impressed many Israelis in Jerusalem but drew criticism from others who said he was interfering in American affairs.

Netanyahu delivered with gusto an address in which he chided Israel's arch-foe Iran and charged that a deal between the Islamic republic and world powers would allow it to develop nuclear weapons.

Israeli Prime Minister Benjamin Netanyahu declared Tuesday that the deal being negotiated between world powers and Iran would leave Tehran free to develop nuclear weapons.

In an impassioned address to the U.S. Congress, conducted even as Secretary of State John Kerry was in nuclear talks in Switzerland with his Iranian counterpart, Netanyahu branded Iran a global threat.

Israeli Prime Minister Benjamin Netanyahu did not forget to blast Hizbullah during his anti-Iran speech before the U.S. Congress on Tuesday, describing the Lebanese party and Tehran as a real threat to Israel's survival.

“For those who believe that Iran threatens the Jewish state, but not the Jewish people, listen to (Sayyed) Hassan Nasrallah, the leader of Hizbullah, Iran's chief terrorist proxy. He said: If all the Jews gather in Israel, it will save us the trouble of chasing them down around the world,” Netanyahu said.

Israeli Prime Minister Benjamin Netanyahu warned Washington on Monday that an emerging nuclear deal with Iran could threaten his country's very survival, but insisted Israel-U.S. relations remain solid.

"You are here to tell the world that reports of the demise of the U.S. relationship is not only premature, but it is wrong," the Israeli leader told delegates to a packed pro-Israel conference in Washington.

U.S. Secretary of State John Kerry on Monday warned Israel's prime minister against revealing details at his upcoming speech to U.S. Congress of an Iran nuclear deal that world powers are in the process of negotiating.

While he did not mention Benjamin Netanyahu by name, Kerry told reporters in Geneva he was "concerned by reports" that "selective details" of the deal aimed at curbing Tehran's nuclear program would be revealed in the coming days.

Israeli Prime Minister Benjamin Netanyahu is "welcome" to deliver his US speech, Secretary of State John Kerry said Sunday, insisting that Washington is eager to avoid a "political football" over the controversial visit.

"The Prime Minister of Israel is welcome to speak in the United States obviously and we have a closer relationship with Israel right now in terms of security than in any time in history," Kerry told ABC television's "This Week" program.

Israeli Prime Minister Benjamin Netanyahu was due in Washington Sunday on what he has called a "historic" quest to stop an international nuclear deal with Iran that the United States is determined to pursue.

Netanyahu's controversial 48-hour visit has stoked discord with U.S. President Barack Obama and brought bilateral relations to their lowest point in years.