By Adrian Blomfield

Iran will attack American military bases in the Persian Gulf if Israel bombs its nuclear facilities, the head of Hizbollah, the militant Lebanese Shia movement, has warned.

Hasan Nasrallah, who has led Tehran’s most powerful proxy group for 10 years, disclosed that Iranian officials were intent on dragging the United States into war if it fails to prevent Israel from taking military action.

“A decision has been taken to respond and the response will be very great,” Nasrallah told Al Mayadeen, a Beirut-based television station.

“The response will not just be inside the Israeli entity. American bases in the whole region could be Iranian targets. If Israel targets Iran, America bears responsibility.”

The purported Iranian threat appears to be designed to prey on President Barack Obama’s greatest fear that he could become entangled in a war not of his own choosing.

His administration has struggled in recent weeks to restrain Israel amid increasingly bellicose rhetoric from its prime minister, Benjamin Netanyahu.

Senior U.S. government officials have spoken of not wanting to be “complicit” in a unilateral Israeli attack against Iran’s nuclear installations, which some have speculated could come before Americans go to the polls in November.

But if Israel were to take action, Obama would come under pressure to side with Israel, seen by many Americans as their closest ally.

If Iran were to make good its threat, he might have no choice but to become involved—presenting him with the most unwanted of distractions as he seeks a second term.

For Israel, the risks of unilateral action are great, although Netanyahu believes they could be even greater if he did nothing and Iran acquired a nuclear weapon.

Apart from its own arsenal of long-range missiles, Iran could unleash proxies like Hizbollah, its Shia protégé, which has an arsenal of tens of thousands of rockets, some capable of reaching Tel Aviv.

Nasrallah did not specifically say he would order Hizbullah into action if Israel did strike at Iran, but he boasted that he could retaliate with huge force if the Jewish state attacked Lebanon. He even hinted that his militants could invade the Galilee.

But he also insisted that Hizbullah would never use chemical weapons against Israel amid fears that Syria’s stockpiles were becoming increasingly insecure as the country civil war grinds on.

“We don’t have chemical weapons and we cannot use them for reasons linked to the Sharia and for humanitarian reasons,” he said.

As tensions mount in the Middle East, the United States is preparing to escalate pressure on Iran by mounting the largest-ever multination minesweeping exercise in the Persian Gulf later this month.

But Iran laughed of the maneuvers on Tuesday.

“The Americans live with the delusion that they are powerful,” said Adm. Ali Fadavi, the most senior naval commander in Iran’s elite Republican Guards.

“But the Islamic Revolution’s power is derived from God’s eternal power and it is incomparable.”

A second naval commander, Adm. Habibollah Sayyari, repeated claims that Iran aims to station its warships in international waters off the American coastline “in the next few years.”