Washington: The United States said it was "very concerned" about a Syrian offensive in Aleppo, Syria, but rejected comparisons to Libya where NATO-led forces intervened last year to protect civilians.

"We are very concerned about the situation in Aleppo," White House spokesman Jay Carney said, condemning Syrian President Bashar Al-Assad's "heinous, reprehensible" assault on Syrian civilians.

"The kinds of weaponry that they're using against unarmed civilians I think demonstrates the depths of depravity to which Assad has sunk," said Carney at his daily press conference.

Carney was asked about the similarities between Aleppo, a restive stronghold for the rebel Syrian Free Army, and Benghazi, the rebel held Libyan city that was an early focus of the uprising against Libyan leader Muammar Gaddafi.

Forces loyal to Gaddafi launched a major offensive against the Benghazi rebels, and were attacked by an international coalition including the United States, which acted to enforce a no-fly zone.

"There were a broader array of issues that allowed for the kind of action that the United States you know, the international community, led by the United States, was able to take in Libya," Carney said.

"There was the imminent assault. There was the call from the opposition, the unified opposition, for international action.

There was international consensus both at the level of the United Nations Security Council as well as regional consensus through the Arab League," he said, adding, "We do not have that" in Syria.

"We've been very blunt about our disappointment with the Russians and the Chinese and the fact that they have vetoed the three meaningful resolutions that were put before the United Nations Security Council with regard to Syria and Assad."

Regime forces fired machine guns into several districts of Aleppo from helicopters on Friday, and were massing for an assault on rebel forces in what is Syria's second largest city.


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