Russia is sending a new shipment of helicopter gunships to Syria, a move that Secretary of State Hillary Clinton said Tuesday could escalate the conflict "quite dramatically."

Syria already has a fleet of the Russian gunships which are armed with rockets, cannons and heavy machine guns.

Syrian President Bashar al-Assad is one of Russia’s main weapons customers, according to Reuters, and Moscow sold a large shipment to the country as recently as mid-May.

Russia’s business relationship with Syria has presented a problem on the U.N. Security Council, which has been seeking a unified stance in confronting the Assad regime. Russia along with China -- two of the council’s five permanent members -- has been reluctant to admonish the Syrian leader, despite the growing bloody toll in a conflict that a U.N. official said Tuesday had all the characteristics of a civil war.

The violence that has left more than 10,000 people dead since the uprising against Assad’s government began 15 months ago. Most of the dead were civilians, according to opposition groups.

It is not clear when this latest batch of attack helicopters is due to arrive in Syria and there is no indication the U.S. would attempt to intercept the shipment. Officials refused to divulge the source of the intelligence reports.

Secretary Clinton disclosed the shipment during a question-and-answer session at the Brookings Institution.

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Meantime, there is a debate as to whether Russia and China have slowed a potential U.N. military intervention in Syria.

In an online question-and-answer for The New Yorker, writer Philip Gourevitch wrote that it was unlikely that Western forces would get involved in the Syrian conflict, even if China and Russia were out of the equation. He said that China and Russia have given "someone for us to blame."

"I'm not at all sure that there's any Western appetite to go into Syria," Gourevitch said.

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"When Russia and China refused to sign on to a toothless resolution condemning Assad and calling for him to step down early this year, Hillary Clinton called their action (or inaction) ‘despicable,'" Gourevitch said. “But without their resistance, we would not look more effective -- and we might look much less effective.”

Msnbc.com's Isolde Raftery contributed to this report.

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