President Barak Obama entered the White House in 2009 carrying an olive branch for Iran, determined to show the world that Washington would not play the villain in a relationship marked by blood and bitterness over three decades, but now it seems that Obama’s olive branch to Iran turned into sanctions hammer.

At present, tensions over Iran's nuclear program have escalated to their highest level in years. Tehran is threatening to block the Strait of  Hormuz and the chances of a miscalculation that could lead to a military clash - and a global oil crisis - appear to be rising.

Diplomacy has led to harsher tactics, with Obama and his European allies trying to isolate the Islamic republic with the toughest sanctions ever.

U.S.-Iran tensions continued to ratchet up, and a string of events made it look to the outside world like an undeclared "soft war" was under way.

The United States accused Iran's shadowy Quds Force  in a plot to assassinate the Saudi ambassador to Washington.

The Stuxnet computer virus attacked centrifuges at Iran's Natanz enrichment facility. Iran accused Israel and the United States. Late last year, the United States lost a spy drone in Iran, unmasking an aggressive surveillance program. Also there have been unexplained explosions at an Iranian missile depot and five nuclear scientists have been killed in Iran - the latest on Wednesday. But US denied any involvement in above issues.

Iran reacted to those events and the stepped-up economic sanctions as if under siege. It threatened to close the Strait of Hormuz, a major oil shipping lane.

According to US officials, the Obama administration is relying on an indirect channel of communication to warn Iran’s supreme leader, Ayatollah Ali Khamenei, that closing the Strait of Hormuz  a “red line” that would provoke an American response.

Senior Obama administration officials have said publicly that Iran would cross a “red line” if it made good on recent threats to close the Strait of Hormuz.  Another American official added this past weekend that the US would take action and reopen the strait which could be accomplished only by military means.

Administration officials and Iran analysts said they believe that Iran’s threats to close the strait, coming amid deep frictions over Iran’s nuclear program and possible sanctions, were bluster and an attempt to drive up the price of oil.

On Sunday, Iran's Foreign Ministry said it has received a US message regarding the Strait of Hormuz via three different channels.

“The US Ambassador to the UN Susan Rice had handed a letter to Iran's Ambassador to the UN Mohammad Khazaei; the Swiss Ambassador to Tehran [Livia Leu Agosti] also conveyed the same thing; and Iraqi President Jalal Talabani delivered the same message to Iranian officials,” Foreign Ministry Spokesman Ramin Mehmanparast said.

Mehmanparast said Iran is studying the letter and “will respond if necessary.” The indirect communications channel was chosen to underscore privately to Iran shows the depth of American concern about rising tensions over the strait.

Previously, Iran’s Supreme Leader Ayatollah Ali Khamenei rejected an offer by US President Barack Obama to open a new era in relations until Tehran could see real changes in US policies.

"The new US president sends us a Persian New Year greeting message but in the same accuses us again to support terrorism and to be after nuclear  weapons.”

"He offers us his hand with a velvet glove under which, however, might be a cast-iron hand,” he added.

However, There is some  questions unanswered. What would happen at the end of the story of the Strait? Will Iran respond to the letter? What would be the answer? They are all covered in a veil of ambiguity.

 

Sources: The New York Times, The Christian Science Monitor, Press TV