Tensions over Iran rose several notches on Wednesday following a series of suspected bomb plots against Israeli diplomats in different countries, and ahead of an expected announcement on Tehran's nuclear progress.
Iranian officials have denied any involvement in the alleged plots in Thailand, India and Georgia this week, rejecting Israeli accusations that the Islamic republic was behind the "terrorist" acts.
At the same time, Iran is poised to unveil what it called "achievements" in its controversial nuclear programme. President Mahmoud Ahmadinejad was to announce the "several" unspecified projects on Wednesday.
The two developments added to geopolitical uncertainty in a worsening showdown between Iran and the West.
Oil prices spiked higher in Asian trade on fears that the confrontation could spill over into military conflict or that Iran could make good on its threats to try to halt all oil shipments out of the Gulf.
Israel has encouraged speculation that it could launch air strikes against Iranian nuclear facilities within months, while the United States has imposed unprecedentedly tough sanctions -- while not taking the military option off the table.
The head of Russia's army, Chief of Staff General Nikolai Makarov, was quoted by the RIA Novosti news agency on Tuesday saying that Western powers were very close to committing to a course of action on Iran.
"Some sort of decision on it should be taken soon. It will probably be taken closer to the (northern) summer," he said.
Unease has heightened markedly following the alleged bomb plots on Monday and Tuesday.
Thai authorities were holding two Iranians in connection with a series of explosions in Bangkok on Tuesday, one of whom lost both his legs from a device he tried to throw at police.
A senior Thai intelligence official told AFP that the two were part of an "assassination team" targeting Israeli diplomats and that "their plan was to attach bombs to diplomats' cars."
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On Monday, an Israeli diplomat in New Delhi suffered grave shrapnel wounds when a motorbike assailant attached a bomb to her car, and in Georgia a similar attack was thwarted when a bomb was detected under an Israeli diplomat's car and defused.
Analysts thought it possible the attacks could be Iranian payback for the murder of four Iranian scientists in Tehran over the past two years by motorbike assailants widely thought to have been sent by Israel.
Israel, certainly, was quick to implicate Iran in the bomb incidents.
"The attempted attack in Bangkok proves once again that Iran and its proxies are continuing to act in the ways of terror and the latest attacks are an example of that," Israeli Defence Minister Ehud Barak said.
But Iranian foreign ministry spokesman Ramin Mehmanparast denied his country was involved in any of the cases and said Tehran condemned any "terrorist action."
He told the official IRNA news agency: "The aim of the Zionist regime's claims is to overshadow the assassination of Iranian scientists."
Ahmadinejad, meanwhile, was to reveal Iran's nuclear progress on "several" fronts on Wednesday.
Iran's deputy nuclear negotiator Ali Baqeri told Russia's RIA Novosti news agency that one of the advances was the production of 20-percent enriched nuclear fuel.
"For the first time, fuel produced by Iranian scientists will be installed in the presence of the Islamic Republic's president in Tehran's research reactor on Wednesday," Baqeri was quoted as saying.
Western analysts had previously cast doubt on Iran's technical ability to create the 20-percent enriched fuel plates needed for the reactor, whose original stock of fuel plates sourced from Argentina in the 1990s is dwindling.
The United States and its allies have expressed fears that the real reason Iran has activities enriching uranium to 20 percent -- instead of the 3.5 percent typically used for producing electricity from reactors -- is to get closer to the 90 percent needed for atomic weapons.
Iran has denied its nuclear programme is anything but peaceful in nature.
The UN nuclear watchdog, however, expressed strong suspicions in November that Iran's programme had a military component. It is to send a high-level delegation back to Iran next week to discuss concerns, following talks in Tehran late last month.