"The total number is probably north of six now," another U.S. official told The New York Times Wednesday. Both officials spoke on condition of anonymity and presidential news secretary Jay Carney declined to confirm the reports of missile firings at his daily White House briefing.
"If true, this would be the last desperate act from a regime that has shown utter disregard for innocent life, utter disregard for the lives of its own citizens," Carney said.
Details on the possible use of Scud missiles, a class of Soviet-era missiles made famous when they were fired by Iraq's Saddam Hussein during Operation Desert Storm, the first Persian Gulf war, were sketchy, The Washington Post reported.
The senior officials said the missiles were launched from Damascus over the past few days but they declined to indicate where they landed in northeastern Syria or say if they caused any deaths or injuries for "intelligence reasons," the newspaper said.
Carney said Syrian President Bashar Assad's use Scuds against his own people would be "another indication of the depravity of Assad and his cronies."
There were also reports by two Lebanese television channels of a deadly car bombing and two other explosions outside the Interior Ministry in Damascus Wednesday that may have killed four people and injured 20.
In Washington, President Barack Obama spoke of his decision Tuesday to declare a newly formed Syrian opposition group the "legitimate representative" of Syria's people in an interview with ABC News.
"We've made a decision that the Syrian Opposition Coalition [of Syrian Revolutionary and Opposition Forces] is now inclusive enough, is reflective and representative enough of the Syrian population and we consider them the legitimate representative of the Syrian people in opposition to the Assad regime," the president said. The full interview will be broadcast later this week.
The National Coalition for Syrian Revolutionary and Opposition Forces, also known as the Syrian National Coalition, was to make its plans public at a Friends of Syria Group summit in Marrakech, Morocco, attended by regional and Western backers of the opposition, coalition officials said.
The plans, hailed as a watershed moment for the movement, would rapidly move hundreds of millions of dollars in humanitarian aid to Syria's most deprived areas, the British newspaper The Guardian newspaper said.
They were intended to cement coalition claims it is the sole alternative to the regime of embattled President Assad, the newspaper said.
Obama said Washington now formally recognized the coalition, paving the way for more U.S. support.
Obama's announcement of Washington's recognition of the coalition followed a U.S. State Department designation of the Salafi jihadi paramilitary group Jabhat al-Nusra, or the al-Nusra Front, as a foreign terrorist organization affiliated with al-Qaida in Iraq.
The U.S. Treasury Department also imposed sanctions against two senior Nusra leaders, citing their ties to al-Qaida in Iraq.
However, other opposition groups, including those in the mainstream, expressed anger over the sanctions against Nusra, an aggressive and successful arm of the rebel forces.
More than 100 anti-regime organizations and fighting battalions called online for demonstrations Friday under the slogan, "No to American intervention -- we are all Jabhat al-Nusra."