U.S. talks with Iran must be based on concrete steps by Tehran: Kerry

(Reuters) - U.S. Secretary of State John Kerry said on Thursday that the United States hopes to engage with the new Iranian administration, but Tehran must first prove it is willing to end the stand-off over its nuclear weapons program.

If Iran intends to be peaceful, "I believe there is a way to get there," Kerry told a news conference in Tokyo after a meeting of U.S. and Japanese defences and foreign ministers.

Kerry expressed hope that engagement with President Hassan Rouhani's government can succeed but said nothing would be taken at face value.

Discussions would be based on a series of steps that guarantee "we have certainty about what is happening," Kerry said.

In a charm offensive at U.N. meetings in New York last week, Iran expressed willingness to resolve the 10-year-old dispute with the United States over its nuclear program, a move that Israeli Prime Minister Benjamin Netanyahu dismissed as a ruse concocted by a "wolf in sheep's clothing".

Addressing Netanyahu's concerns over talks with Iran, Kerry said: "We are firmly determined that Israel's security remains paramount."

He dismissed suggestions that the United States was being played by Iran.

"There is nothing here that is going to be taken at face-value and we've made that clear," Kerry said. "The president has said, and I have said, that it is not words that will make a difference, it's actions, and the actions are clearly going to have to be sufficient."

The United States, Israel and other countries accuse Iran of using its nuclear program to try to develop the capability to produce weapons. Iran says the program is for peaceful purposes only.

"It would be diplomatic malpractice of the worst order" for the United States not to explore opportunities, said Kerry, who met his Iranian counterpart Mohammad Javad Zarif at the United Nations last week, the highest-level official meeting between the United States and Iran in more than three decades.

"We are going to look very very carefully at this. We hope it could work because we think the world would be better off," Kerry said, adding: "A country that genuinely wants to have a peaceful program does not have difficulty proving that it is in fact peaceful, so this ought to be able to be done.

"The test we face over these next weeks and months, not a long period of time, is to determine whether or not that is in fact what Iran intends," Kerry added.