Washington, May 14
At a meeting of US President Donald Trumps top national security aides last week, Acting Defence Secretary Patrick Shanahan presented an updated military plan that envisions sending as many as 120,000 troops to the Middle East should Iran attack American forces or accelerate work on nuclear weapons, administration officials said.

The high-level review of the Pentagon's plans was presented during a meeting on May 9 about broader Iran policys, The New York Times quoted the officials as saying on Monday.

It was held days after what the Trump administration described, without evidence, as new intelligence indicating that Iran was mobilising proxy groups in Iraq and Syria to attack American force.

As a precaution, the Pentagon has moved an aircraft carrier, B-52 bombers, a Patriot missile interceptor battery and more naval firepower to the Gulf region.

The revisions were ordered by hard-liners led by John Bolton, Trump's National Security Adviser. They however, did not call for a land invasion of Iran, which would require vastly more troops.

It remains uncertain whether Trump, who has sought to disentangle the US from Afghanistan and Syria, ultimately would send American forces back to the Middle East.

It is also unclear whether the President has been briefed on the number of troops or other details in the plans.

On Monday, when asked about if he was seeking regime change in Iran, Trump said: "We'll see what happens with Iran. If they do anything, it would be a very bad mistake."

"It's going to be a bad problem for Iran if something happens," he added.

European allies who met Secretary of State Mike Pompeo on Monday said that they were worried that tensions between Washington and Tehran could boil over, possibly inadvertently.

According to The New York Times, deploying such a robust air, land and naval force would give Tehran more targets to strike, and potentially more reason to do so, risking entangling the US in a drawn out conflict.

It also would reverse years of retrenching by the American military in the Middle East that began with former President Barack Obama's withdrawal of troops from Iraq in 2011.

The report comes as several oil tankers were reportedly attacked or sabotaged off the coast of the United Arab Emirates on Sunday.

Saudi Arabian officials are investigating the apparent sabotage, and American officials suspect that Iran was involved.

An Iranian Foreign Ministry spokesman called it a "regretful incident".

US assessment blames Iran for Saudi tankers attack

An initial US assessment has indicated that Iran was likely to be behind the attack on two Saudi Arabian oil tankers and two other vessels damaged over the weekend off the coast of the United Arab Emirates (UAE), an American official said.

The assessment, while not conclusive, was the first suggestion by any nation that Iran was responsible and comes after a series of US warnings against aggression by Tehran or its allies and proxies against military or commercial vessels in the region, reports Efe news.

The US official on Monday didn't offer details about what led to the assessment or its implications for a possible American response.

Last week, the US said that it was sending an aircraft carrier, an amphibious assault ship, a bomber task force and an anti-missile system to the region after it alleged intelligence showed Iran posed a threat to its troops.

"If they do anything, they will suffer greatly. We'll see what happens with Iran," President Donald Trump said while meeting Hungary's Prime Minister Viktor Orban at the White House earlier on Monday.

The Saudi tankers were among at least four oil-industry vessels, including ships from Norway and the UAE, attacked on Sunday in the Gulf of Oman off the UAE's eastern coast just outside the Strait of Hormuz as they prepared to cross into the Persian Gulf.

The attacks caused "significant damage to the structures of the two (Saudi) vessels," Saudi Energy Minister Khalid al-Falih said on Monday, calling the incident "sabotage".

Falih said one of the ships was headed to the Saudi port of Ras Tanura on the Persian Gulf to load oil bound for the US.

Neither Saudi Arabia nor the UAE have publicly blamed Iran for the attack so far.

The attacks sent oil prices higher and heightened worries about global supplies amid petroleum-production outages because of unrest in Venezuela, a civil war in Libya and sanctions on Iran.

Saudi and American US officials have long worried about the Strait of Hormuz becoming a battleground should tensions with Iran break out into open conflict.

A third of the world's liquefied natural gas and almost 20 per cent of total global oil production flows through the Strait of Hormuz for export from Persian Gulf countries. Cutting off oil shipped through the strait would cause shortages and soaring prices.

Meanwhile Iran, which borders the Strait of Hormuz, called the incident "worrisome and dreadful" and called for a full investigation.

White House reviews military plans against Iran