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Syrian President Bashar Assad "is on his way out" and "the balance has shifted" in favor of his departure, senior administration officials said Thursday after President Obama issued a statement calling on the authoritarian leader to resign.

His "days are numbered," concurred the trio of officials, who offered their assessments in a background conference call following Secretary of State Hillary Clinton's televised remarks elaborating the president's position.

Still, the officials acknowledged that they expect the Syrian people to face continued "struggle and sacrifice."

The officials said Acting U.S. Ambassador to Syria Robert Ford remains in touch with the regime in Damascus, including contacts with Syrian officials as recently as this week.

Thursday marked the third round of sanctions the U.S. has imposed on Syrian officials and entities since the rebellion there began, with the previous two rounds coming on April 29 and May 18.

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In all, some 32 Syrian and Iranian individuals and entities have now been subjected to these sanctions, including individuals characterized by the administration as "corrupt cronies" of Assad.

An estimated 90 percent of Syrian oil exports go to European Union countries, the officials said, noting that the concerted actions today by the European Union and individual states in Europe will have the effect of "choking off" Syria’s ability to prosecute its campaign of suppression against its own people.

The U.S. handling of the Egyptian revolution and the Syrian rebellion is markedly different. In the case of the former, Obama himself appeared before cameras less than a week after the uprising began to demand that longtime ally Hosni Mubarak step down. In all, some 300 people were killed throughout the entire Egyptian crisis.

In the case of Syria, the administration waited five months and witnessed some 1,800 casualties, before the president -- in a paper statement -- called on Assad, a designated sponsor of terrorism, to step down.

The officials noted that "each country will change in its own way," and that when Obama spoke out on Mubarak, it was at "the peak" of the protests in Egypt and in line with the tone and desires of the Egyptians.

As for Libya, they said, the U.S. mustered an international coalition to prevent a massacre in Benghazi, adding that Muammar al-Qaddafi's days are "numbered" and that "the metrics are moving against him."

In Syria, the officials said they have been moving in the direction of Thursday's actions for "a period of time," but have been instituting progressively more "punitive measures" against Assad "from the beginning."

The actions, they said, were prompted by the "uptick" in "horrific brutality" witnessed at the outset of Ramadan, and by the realization that Assad's pledge to pull back his military forces was "a lie and an empty promise."

The officials also cited the need to take time to organize Thursday's actions -- not a unilateral move by the U.S. but a concerted one with allies. Heads of state in the United Kingdom, France and Germany also issued a joint statement calling on Assad to go.