JERUSALEM, Israel - Israeli Prime Minister Benjamin Netanyahu called for a "credible military threat" against Iran, saying economic sanctions are not enough to deter it from developing nuclear weapons.

Netanyahu made the remarks in New Orleans on Sunday during a meeting with Vice President Joe Biden on the sidelines of the Jewish Federations of America General Assembly.

"Sanctions are important," Netanyahu said, according to his spokesman, Mark Regev.

"They are increasing pressure on Iran. But so far there has not been any change in the behavior of Iran and upgrading of international pressure is necessary," he said.

Defense Secretary Robert Gates, in Australia for security meetings, rejected Netanyahu's call for a "credible military threat."

Gates told reporters that while "all options" remain on the table," he believes sanctions "are biting more deeply" than anticipated.

"I disagree that only a credible military threat can get Iran to take the action it needs to end its nuclear weapons program," Gates said.

"We are prepared to do what is necessary. But at this point we continue to believe that the political, economic approach that we are taking is, in fact, having an impact on Iran," he said.

Last week, outgoing Israeli military intelligence chief Maj.-Gen. Amos Yadlin said Iran has already produced enough highly enriched uranium to build at least one nuclear bomb. The International Atomic Energy Association - IAEA - and the CIA have drawn similar conclusions in the past.

Meanwhile, Biden assured participants at the General Assembly that the Obama administration is committed to keeping Iran from acquiring nuclear weapons and to helping Israel defend itself from the Islamic Republic.

The vice president said the U.S. remains a stanch supporter of the Jewish state and dismissed strained incidents with the administration as "tactical in nature, never fundamental."

Biden said attempts to delegitimize Israel's right to exist would be met with "unshakable resistance" by the U.S. government.