US bolsters military presence in the region as Iranian parliament threatens to shut Strait of Hormuz to countries backing sanctions

The US and Iran have raised the military stakes in the Gulf as scientists from Tehran and six major powers gathered in Istanbul to try to resolve the Iranian nuclear impasse.

The US was reported to have increased its military presence in the region in recent months, doubling the number of minesweepers while bringing in stealth warplanes partly as a deterrent to any Iranian attempt to close the Strait of Hormuz, a choke point on the Gulf through which a fifth of the world’s oil supply flows.

Meanwhile, as part of extensive war-gamesknown as Great Prophet Seven, Iran test-fired an array of missiles on Tuesday, including the short-range Shahab 1 and Shahab 2 and medium-range Shahab 3, which the state news agency Irna pointed out were capable of striking US ships in the Gulf.

In Tehran, Iran’s parliament called an urgent debate on a bill to block at least some oil tankers in the Gulf, and there were also signs the leadership might be considering the announcement of a new, higher level of uranium enrichment.

The talks at an Istanbul hotel were arranged as a means of keeping diplomatic channels open after high-level negotiations stalled in Moscow last month. The US delegation was led by the administration’s two most senior non-proliferation experts, Gary Samore and Robert Einhorn, while the Iranian team was led by Ali-Reza Asgari, a legal adviser to the Iranian Atomic Energy Organisation and foreign ministry.

The aim is ostensibly to explore whether a lack of understanding of the science involved was blocking a compromise. “The experts are there to explain our position and respond to Iranian questions on a technical level,” a European diplomat said.

The UK also sent a senior diplomat to gauge whether there has been any change to Iranian positions since an EU oil embargo came into force on Sunday. The signals so far from Tehran suggest a hardened stance. Parliament, the Majlis, requested a debate on a bill calling for the Strait of Hormuz to be closed to shipping from countries supporting sanctions.

The foreign ministry spokesman, Ramin Mehmanparast, said if the Majlis did call for such measures, the government would be obliged to follow its directives. However, in a poll on the state news website www.irinn.ir, 78% of respondents disapproved of the Majlis initiative and many called for more conciliatory gestures.

There were also signs the leadership could be preparing to announce an increase in the level to which it enriches uranium. In a bill passed onTuesday, the Majlis called on the government to start building ships “not reliant on fossil fuels” – a reference to an announcement by the Iranian navy last month that it was planning to build nuclear-powered submarines. Such vessels can use anything from the 20%-enriched uranium which Iran is making, to 90%, weapons-grade fuel.

There were unconfirmed reports from Tehran yesterday that President Mahmoud Ahmadinejad was preparing to announce a new target for enrichment between those two levels. Such a move would be seen as provocative by much of the international community, as it would bring Iran far closer to the capacity to make the fissile core for a nuclear weapon.

Tehran has insisted its nuclear aspirations are entirely peaceful, but the UN security council has demanded its uranium enrichment be suspended until it can prove its peaceful intent.

Israel has threatened to take military action against Iran’s nuclear sites, claiming that Tehran’s production of 20% uranium, much of it an underground site, represents an intolerable threat to its security. Israel is the only nuclear-armed state in the Middle East.

The New York Times reported yesterday that the US Navy had doubled the number of its minesweepers in the Gulf to eight, as well as a floating operations platform, the USS Ponce, which could be used as a base for minesweeping operations, humanitarian activities or combat. Two American aircraft carriers, the USS Lincoln and the USS Enterprise are currently in the region.

The minesweeper deployment had been previously reported by the strong rhetoric from American officials, suggesting they were seeking to underline the significance of the move. “The message to Iran is, ‘Don’t even think about it,’” an unnamed senior Pentagon official was quoted as saying. “Don’t even think about closing the Strait. We’ll clear the mines. Don’t even think about sending your fast boats out to harass our vessels or commercial shipping. We’ll put them on the bottom of the Gulf.”

The report also said the US Air Force has been reinforcing its presence in the region since late spring, bringing in stealth F-22 and more conventional F-15C warplanes, giving it a greater ability to strike coastal anti-ship missile batteries as well as other targets further inland. John Pike, head of a US military analysis thinkthank, GlobalSecurity.org, said the deployments also carried a message to Israel. “It is all part of a larger pattern of activity that says we are serious about Iran, and please don’t do anything before the [US presidential] election,” he said.

High-level diplomatic talks on the Iranian nuclear programme were suspended last month after a meeting between the six powers and Iran in Moscow failed to close a wide gulf between the opposing negotiating positions.

The six-nation group, comprising the US, UK, France, Germany, Russia and China, offered a range of incentives if Iran stopped produced 20%-enriched uranium. Iran in response called for the lifting of all sanctions and international recognition of its right to enrich in principle, before it would discuss curbing its 20% enrichment.

In a second opinion poll on the state-run Irinn.ir website, 61% of Iranian respondents said Iran should suspend 20% enrichment in response to the sanctions.

The sabre-rattling around the Gulf drove up oil prices to more than $100 for Brent crude. The International Monetary Fund has estimated Iran needed an oil price of $117 to balance its budget.