Updated

HERZLIYA, Israel -- Iran's suspected nuclear weapons installations are vulnerable to possible military strikes, Israel's vice premier warned Thursday, suggesting that underground bunkers don't offer sufficient protection.

The comments by Moshe Yaalon contradicted an assessment shared by foreign experts and Israeli defense officials that it would be difficult to strike sensitive Iranian nuclear targets, as they are being built underground.

The international community has grown increasingly worried that Israel could be preparing to strike Iran's nuclear program. Yaalon, who also serves as strategic affairs minister, gave no indication that Israel is close to a decision on an attack.

U.S. Defense Secretary Leon Panetta recently said even the most sophisticated U.S. bunker-buster bombs aren't powerful enough to penetrate all of Iran's defenses.

Yaalon, a former military chief of staff, suggested Thursday that forces guarding the nuclear installations could be targeted. Referring to the debate over bunker-buster bombs, he said that "at the end of the day it's possible to strike all the installations."

At an academic conference, Yaalon and Israel's chief of military intelligence, Maj. Gen. Aviv Kochavi, presented details about Iran's weapons programs.

Yaalon said Iran is trying to develop missiles that could target the United States with a range of 6,250 miles. The vice premier said this was discovered in the aftermath of a mysterious explosion several months ago at what he described as a missile research and development site in Iran. The cause of the blast remains unknown, and Yaalon did not elaborate.

Iran insists the blast was accidental, but speculation over sabotage remains strong. The remarks by Yaalon appeared to be the first public suggestion that the missile site was the scene of highly advanced projects and could boost suspicions that outside forces played a role in the explosion.

Israel has been a leading voice in the international calls to curb Iran's nuclear program. Iran denies it's trying to develop nuclear weapons, insisting it seeks nuclear power for nonmilitary uses.

Kochavi told the conference that Iran has already produced enough enriched uranium to eventually make four nuclear bombs. Such material would serve as the basis for further enrichment, up to weapons grade.

Israeli media quoted Kochavi as saying that once Iran moves into the so-called "breakout stage" and decides to produce weapons grade uranium, it would need about a year to make a rudimentary bomb and an additional year or two to craft a nuclear warhead.

"Iran keeps advancing its capabilities, keeps developing its very ambitious nuclear program, at the basis of which is to get nuclear power," Kochavi said.

An Iranian counterstrike at Israel is seen as likely if Tehran's nuclear installations are attacked.
Kochavi said Israel's enemies have about 200,000 rockets and missiles that could strike Israel. Most have a range of about 25 miles, but several thousand have a range of several hundred miles, he said.

Iranian proxies in the region, mainly Gaza's Islamic militant Hamas and the Lebanese Hezbollah, have fired thousands of rockets into Israel and have been building up their arsenals in recent years.