Prime Minister Benjamin Netanyahu on Thursday told the Knesset that Tehran was behind the recent rocket barrages from the Gaza Strip and ratcheted up his rhetoric regarding a possible military strike on Iran, broadly hinting that Israel might act even without American approval.

"The dominant force behind the events in Gaza is not the Palestinians, but Iran," Netanyahu said. "The terror groups there stand under an Iranian umbrella. Imagine to yourselves what will happen when that umbrella is armed with nuclear bombs."

Alluding to the success of the Iron Dome antimissile system, Netanyahu said, "I want to make it clear: There is no hermetic defense, and there never will be. A combination of offensive capabilities, defensive capabilities and national resilience is the winning combination, and that's what we must cultivate," he said, but added, "Sooner or later the Iranian terror base in Gaza will be uprooted."

Netanyahu also mentioned his visit to the United States last week, saying, "The right of Israel to defend itself was accepted in the United States in the most positive, deepest way possible. [This right] has the absolute backing of the American people, the wall-to-wall support of the American Congress and the official backing of the White House."

During his address, however, Netanyahu cited three instances in which Israeli prime ministers acted against the position of the United States: David Ben-Gurion's declaration of independence in 1948, Levi Eshkol's actions in the period leading up to the 1967 Six-Day War and Menachem Begin's 1981 decision to attack the nuclear reactor in Iraq.

Netanyahu stressed the importance of Israel's alliance with the United States, but said, "Even more prominent is our obligation to be masters of our own fate. Israel never left its fate in the hands of others, not even those of our best friends."

U.S. President Barack Obama also referred to the Iran issue on Thursday, during a joint press conference with British Prime Minister David Cameron in Washington.

Obama stressed his determination to prevent Iran from obtaining nuclear weapons.

"This is an issue that is important to the entire international community," Obama said, and one on which he and Cameron were in complete agreement.

"I have sent a message very directly to them, publicly, that they need to seize this opportunity of negotiations with the P-5-plus-one [the five permanent members of the UN Security Council - Britain, China, France, Russia and the United States - plus Germany] to avert even worse consequences for Iran in the future," Obama said, in reference to the Tehran leadership. "I think they should understand that because the international community has applied so many sanctions, because we have employed so many of the options that are available to us to persuade Iran to take a different course, that the window for solving this issue diplomatically is shrinking," the U.S. president said.

According to a Russian report, the United States is not merely calling on Iran to return to negotiations, but is sending much harsher messages.

The Moscow-based Kommersant reported that the United States asked Russia to convey to Iran that the meeting of the six powers in April would be Iran's last chance to avoid a military attack on its nuclear facilities.

The paper attributed the information to a Russian Foreign Ministry official, who also told the paper that the warning was delivered by U.S. Secretary of State Hilary Clinton to her Russian counterpart Sergei Lavarov at their meeting in New York on Monday.

The American people do not seem interested in plunging into another war. According to a new poll conducted by the University of Maryland, only one out of four Americans would like to see Israel attack Iran's nuclear facilities, while 69 percent would prefer to see the United States continue a dialogue with Iran.