Israeli Prime Minister Ariel Sharon says his country's "ambiguous" nuclear policy is working and will continue.
Sharon said Israel would not change its "no show, no tell" policy
His comments came hours before the head of the UN's International Atomic Energy Agency, Mohamed ElBaradei, arrived for talks in Israel.
Mr ElBaradei is expected to press for a nuclear arms-free zone in the region.
Israel is widely believed to have a large stockpile of nuclear warheads, but it refuses to confirm or deny that it has a nuclear deterrent.
Mr ElBaradei arrived on Tuesday evening, with the main meetings due to take place on Thursday.
He told reporters he did not expect Israel to reveal its nuclear secrets, but wanted to see "the beginning of a dialogue on how a... nuclear security free zone could look".
"If I get the parties closer on the need for a dialogue, I think I'll be successful," he said.
Before the visit, Israel released photos of its nuclear plant in the Negev desert for the first time.
The images appear on a new website for the Israeli Atomic Energy Commission. Analysts believe Israel has about 200 warheads at the plant in the town of Dimona.
But there is little sign that Israel is set to be more open about its nuclear activities, the BBC's diplomatic correspondent Jonathan Marcus says.
Mr Sharon, quoted by Israeli Army Radio, said the country did not intend to change its "no show, no tell" policy of nuclear ambiguity.
"I don't know what he [ElBaradei] is coming to see," Mr Sharon said.
"Israel has to hold in its hand all the elements of power necessary to protect itself by itself.
"Our policy of ambiguity on nuclear arms has proved its worth, and it will continue," Mr Sharon added, without elaborating.
In December, Mr ElBaradei urged Israel - a member of the IAEA - to surrender its alleged nuclear weapons.
But, unlike Iran and North Korea - two nations whose alleged nuclear ambitions have recently come under international scrutiny - Israel has never signed the Nuclear Non-Proliferation Treaty, designed to prevent the global spread of nuclear arms.
As a result, it is not subject to inspections or the threat of sanctions by the IAEA.
With a programme dating back to the early 1950s, Israel is widely believed to have become a fully-fledged nuclear armed power.
When compared with India and Pakistan - other states that have relatively recently developed nuclear arms - Israel's deterrent is probably the most sophisticated, our correspondent says.
It can be delivered by long-range ballistic missiles or advanced warplanes. Some reports suggest that Israel is even developing a submarine launched missile that might carry a nuclear warhead.