WASHINGTON (AFP) – The United States has piled pressure on Iran ahead of key nuclear talks, demanding full access to Tehran’s newly revealed uranium plant and denouncing “provocative” new missile tests.

“This is an important day, and an important week for the Iranians, they have decisions to make,” said White House spokesman Robert Gibbs, in the run-up to Thursday’s meeting in Geneva between world powers and Iran.

Russia, meanwhile, expressed concern at test-firings by Iran’s Revolutionary Guards of surface-to-surface Sejil and Shahab-3 missiles, both of which Tehran says are capable of hitting targets in Israel.

It was the latest sign of a common concern over Iran between Russia and the United States, following talks between Russian President Dmitry Medvedev and US President Barack Obama in New York last week.

Gibbs argued that the world had never been more united on challenging Iran’s nuclear program, and Tehran never more alone, attempting to play on the apparently increasing isolation facing the Iranians over their nuclear program.

Washington demanded Tehran throw open the previously secret uranium enrichment plant buried in a mountain near the holy city of Qom, to International Atomic Energy Agency (IAEA) inspectors. Facts: Iran’s missile arsenal

“They can… agree to immediate, unfettered access. I think that would be the least that they can do,” Gibbs said.

“I don’t believe that there’s ever been as broad and as deep a consensus about addressing the concerns that we have right now.”

The White House and the State Department also strongly condemned Iran’s latest missile tests.

State Department spokesman P.J. Crowley said the tests were “not helpful at all.

“To the extent that Iran wants to continue to act more like a police state or a military state than a constructive player in the region, it just will further isolate Iran.”

Gibbs said: “I would lump any of these into the provocative nature with which Iran has acted on the world stage for a number of years.” He added, however, that the tests appeared pre-planned and not directly related to the Geneva talks.

He said they validated Obama’s decision to switch from a missile defense system in Eastern Europe targeting long-range Iranian missiles to a program concerned more with short and medium range Iranian ballistics.

Crowley warned that Iran would fail, if its motivation was to try to influence Thursday’s P5-plus-one talks between Iran’s top nuclear negotiator Saeed Jalili and the permanent five members of the UN Security Council plus Germany.

“It just will further isolate Iran, and you’ll continue to see greater international consensus for additional steps, including sanctions against Iran.

“This provocative behaviour did not work for North Korea, it’s unlikely to work for Iran.”

Russia also expressed concern over the Iranian missile tests.

“It is not prohibited by any international agreement, but of course when missile launches occur on top of the unresolved situation surrounding Iran’s nuclear programme, it’s worrying,” Russia’s Foreign Minister Sergei Lavrov said, according to news agencies.

Another key player is China, which has yet to match Medvedev’s hint that tough new sanctions might be necessary, should Iran not meet foreign concerns.

The top US diplomat handling Asia said that Beijing was coming around on the need for tougher action against Iran, after talks last week between Chinese and US officials on the sidelines of the Group of 20 summit in Pittsburgh.

“For the first time, really, the Chinese supported elements of our tough approach on the P5-plus-one,” said Kurt Campbell, assistant secretary of state for East Asian and Pacific affairs.

Talk of more sanctions has been swelling ahead of the Geneva meeting between Iran, the United States, Russia, China, Britain, France and Germany in Geneva.

But Iran has so far been defiant and Iranian armed forces chief of staff General Hassan Firouzabadi on Monday dismissed Israeli threats out of hand.

“Israel is a paper tiger and when they say that Israel is going to attack Iran it is a bluff,” Firouzabadi said, quoted by the Mehr news agency.

Tehran admitted last week building a uranium enrichment plant at the Qom site, its second after a facility in Natanz, in defiance of repeated UN demands for a halt to all enrichment activities until the IAEA can vouchsafe that they are entirely peaceful, as claimed by the Islamic republic.

Enriched uranium can be used to make nuclear fuel, but also the fissile material for an atomic bomb.