Dubai: The escalating tension between Iran and the international community yesterday took a grim turn that military experts said could be "indicators of war, but would not lead to a military conflict".

Israel is preparing to shut its nuclear reactor at Dimona citing the site's vulnerability to a missile attack, feared to come from Iran, press reports said.

As both the US and Israel are preparing for what is being described as the largest ever joint drills by the two countries, senior US military officials warned that if Iran executes its threats and closes the strategic Strait of Hormuz, it will be crossing a "red line".

"We made it very clear that the United States will not tolerate the blocking of the Strait of Hormuz," US Defence Secretary Leon Panetta was quoted as saying yesterday.

Iran has the ability to block the Strait of Hormuz "for a period of time," and the US would take action to reopen it, Joint Chiefs of Staff chairman General Martin Dempsey said.

Iran's army chief warned last week that American warships that exited from the Arabian Gulf for the country's just-concluded 10-day military drill shouldn't return.

"The Islamic Republic of Iran doesn't intend to repeat this warning," official Iranian media quoted Major General Ataollah Salehi as saying. "All these are indicators to war, but they will not lead to an actual war," said Mohammad Abdul Salam, an Egyptian military expert.

"We are talking about real indicators that are related to credible threats that don't aim to launch an attack against Iran, but rather to push Iran to retreat from what it could do: close Hormuz," he told Gulf News.

Both sides, Iran and the US are trying to avoid a war, and they don't aim to engage in one, experts believe, and they are "sending each other a message: don't push me to enter a war."

No exact date for the US-Israeli exercise has been announced but a senior military official said he expected it in the next few weeks.

— With additional input from agencies