Top US military chief General Martin Dempsey arrived in Israel on Thursday, the US embassy said, for talks with political and military leaders that are expected to focus on Iran's nuclear programme.

Dempsey's trip is his first to Israel since becoming chairman of the Joint Chiefs of Staff in October.

His brief trip will include talks with Chief of Staff Lieutenant General Benny Gantz, Defence Minister Ehud Barak and Prime Minister Benjamin Netanyahu.

Dempsey will also meet President Shimon Peres and visit Israel's Holocaust museum Yad Vashem before leaving on Friday evening.

His discussions are expected to focus on Iran's nuclear programme, which both Washington and Israel fear masks a weapons drive.

Tehran denies those charges, saying the programme is for peaceful energy and medical purposes. However, it faces increasingly tough international sanctions against its oil exports and financial institutions in a bid to force an end to its uranium enrichment efforts.

Israel fears a nuclear-armed Iran would pose an existential threat to the Jewish state and has raised the prospect of military action against Tehran's nuclear activities.

But the United States has stressed the importance of pushing forward with sanctions and is believed to have privately warned Israel against undertaking unilateral military action.

On Wednesday, Barak tried to calm speculation about the possibility of an impending military strike, saying Israel was "very far away" from such a decision.

"We don't have a decision to go forward with these things. We don't have a decision or a date for taking such a decision. This whole thing is very far away," he told army radio.

He also denied reports suggesting Dempsey had been sent to Israel to convince it to refrain from military action.

"The chairman of the joint chiefs of staff is not coming with a view to putting pressure on the state of Israel," Barak said.

"The United States knows that Israel takes American considerations into account, but the Israeli government... (is) responsible for the security of the state of Israel and we cannot set aside this responsibility for anyone, including our American friends."