A top US security official met Israeli Prime Minister Benjamin Netanyahu on Sunday amid rising concerns over Iran and ahead of a trip by the Israeli premier to Washington.
Public radio said he and US National Security Advisor Tom Donilon had a two-hour meeting that focused on "regional threats," despite Netanyahu's office refusing to confirm any meeting or to comment.
The White House had said Donilon would discuss a range of issues with senior Israeli officials, including Syria, and an Israeli official had said he would meet Netanyahu on Sunday afternoon.
The visit comes at a time of heightened tension between Israel and Iran over Tehran's nuclear programme, and after attacks on Israeli diplomats blamed on agents of Tehran.
In recent weeks, there has been feverish speculation that Israel was getting closer to mounting a pre-emptive strike on Iran's nuclear programme, though Israel has denied reaching such a decision.
Tensions between Iran and Israel also have been simmering with Iranian warships entering the Mediterranean in a show of "might," a move Israel said it would closely monitor.
Netanyahu said at Sunday's weekly cabinet meeting that on the agenda was a review by defence officials of the state of Israel's civil defence readiness.
"This is part of continuous action we have been taking in recent years in order to prepare Israel for the new age," he said. "An age of threats to the Israeli home front." He did not elaborate.
On Sunday night, Netanyahu spoke to a conference of the presidents of Jewish American organisations, and said Israel faced "four threats."
"The first is nuclear, the second is missiles with many thousands aimed at Israel and its cities, the third is cyber attacks, the fourth is border infiltration not only by terrorists, but by mainly foreigners who threaten the Jewish nature of our small state."
A military spokesman said on Sunday that a battery of rocket interceptors from its "Iron Dome" system would be deployed in the Tel Aviv area from Monday.
Designed to intercept rockets and artillery shells fired from a range of between four and 70 kilometres (three and 45 miles), Iron Dome is part of an ambitious multi-layered defence programme to protect Israeli towns and cities.
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Israeli media on Sunday quoted a CNN interview with the chairman of the US Joint Chiefs of Staff, General Martin Dempsey, warning that an Israeli military strike on Iran would be "destabilising."
"It’s not prudent at this point to decide to attack Iran," the Jerusalem Post quoted him as saying in a transcript of the interview.
"The US government is confident that the Israelis understand our concerns," it quoted Dempsey as saying.
"A strike at this time would be destabilising and wouldn’t achieve (Israel's) long-term objectives."
Israel's former national security adviser Uzi Dayan called Dempsey's choice of words significant.
"I would emphasise Martin Dempsey's use of the phrase 'at this point'," he told public radio, pointing to Iran's latest offer to resume stalled nuclear talks with the five permanent UN Security Council members -- the United States, Russia, China, France and Britain -- plus Germany.
The United States, other Western powers and Israel believe that Iran is seeking to build a nuclear bomb, but Tehran denies the charge, insisting its atomic programme is for purely peaceful purposes.
Israel is widely believed to be the sole nuclear-armed power in the Middle East, albeit undeclared.
Donilon's visit comes ahead of a trip in early March by Netanyahu to Washington for talks with US President Barack Obama which are likely to focus on Iran and stalled peace talks between Israeli and Palestinian negotiators.
Top-selling Israeli daily Yediot Aharonot said on Sunday that US Director of National Intelligence James Clapper would visit Israel later in the week for talks with defence and intelligence officials.
Both Clapper and Donilon "plan to deliver a calming message, that even if talks are resumed with Iran, this will not be at the expense of the sanctions, which will continue to mount unless Iran puts an immediate halt to its nuclear programme and allows serious supervision," the paper said.
It added that Defence Minister Ehud Barak would make a preparatory trip to Washington ahead of Netanyahu.