(CNN) -- Sanctions aimed at stopping Iran from developing nuclear weapons are having an impact on that country, U.S. Defense Secretary Robert Gates said Monday.
"We know that they are concerned about the impact of the sanctions. The sanctions are biting more deeply than they anticipated, and we are working very hard at this," he told reporters in Australia.
He said he disagreed with a recent assertion by Israeli Prime Minister Benjamin Netanyahu that a military threat was the only way to influence Iran's nuclear policies.
"I disagree that only a credible military threat can get Iran to take the actions that it needs to, to end its nuclear weapons program. 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.
But Gates noted that "when it comes to Iran, all options are on the table."
The United States and other countries believe Iran is trying to develop the technology to build a nuclear bomb, but Tehran consistently denies its program has a military aim.
Iran is now subject to four sets of U.N. sanctions, while the United States and the European Union have also imposed separate penalties on Iran over its refusal to stop enriching uranium.
Still, Iranian President Mahmoud Ahmadinejad has said his country's resolve has not diminished.
"They thought they can weaken the Iranian nation through imposing sanctions and posing threats, but Iranians have showed integrity, convergence and strength," he said in October.
CNN
