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U.S. Secretary of State Hillary Clinton met with Russia's top diplomat Thursday to discuss the crisis in Syria, a day after sources confirmed to Fox News Syria's military has mixed chemical weapons and loaded them into bombs in preparation for possible use on President Assad's own people.

The Associated Press reports Clinton met with Russian Foreign Minister Sergey Lavrov in Ireland on Thursday, and the two were scheduled to discuss a way forward in Syria later with the U.N. envoy to Syria, Lakhdar Brahimi.

A senior U.S. official told Fox News Wednesday that Syrian forces had loaded bombs with components of sarin gas, a deadly nerve gas. They have 60 days to use these bombs until the chemical mixture expires and has to be destroyed.

U.N. Secretary General Ban Ki-moon reportedly wrote to Assad Thursday urging him not to use chemical weapons, saying that "any use of such weapons would be an outrageous crime with dire consequences," according to Reuters.

NBC News, which first reported this latest escalation in the Syrian civil war, cited sources saying bombs filled with a sarin component have not yet been loaded onto planes, but the Syrian military is prepared to use these chemical weapons against civilians pending orders from Assad.

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The sarin could be delivered in several ways but is believed to have been placed in fracturable canisters that can be dropped from planes, according to a senior US military source.

"We think they have it in aerosol form," the source told Fox News.

The United States has said chemical weapons use would be unacceptable and would trigger greater Western intervention in the conflict.

The U.S. military is making contingency plans should Assad leave suddenly. Various Middle Eastern countries are trying to find a place to give Assad asylum, according to Middle Eastern diplomatic sources.

In Brussels earlier Wednesday, Clinton reiterated concerns that "an increasingly desperate Assad regime might turn to chemical weapons" or lose control of them to militant groups.

She also said NATO's decision on Tuesday to send Patriot missiles to Turkey's southern border with Syria sends a message that Ankara is backed by its allies. The missiles are intended only for defensive purposes, she said.

Syria's deputy Foreign Minister Faisal Mekdad insisted the deployment of the missile defense system would not affect the determination of President Bashar Assad's government to crush the "terrorists," using the regime's term for rebels fighting to topple the longtime leader.

Mekdad denounced the NATO move and the chemical weapons "chorus" as part of a conspiracy that is possibly laying out the foundations for a military intervention in Syria.

Syria has been careful not to confirm it has chemical weapons while insisting it would never use such weapons against its own people

"I repeat for the hundredth time that even if such weapons exist in Syria, they will not be used against the Syrian people," Mekdad said in an interview with Lebanon's Al-Manar TV station. "We cannot possibly commit suicide, Syria is a responsible country."

Violence in Syria, meanwhile, persisted. A booby-trapped car exploded outside the offices of the Red Crescent society in the al-Zahera neighborhood of Damascus, killing one person, according to state television.

A video posted online purporting to show the blast site showed rubble strewn about a residential street and walls and windows blown out of nearby three-story buildings.

The video appeared genuine and was in line with what state media reported. The Syrian government bars most journalists from working independently in the country.

It's the latest in a series of bombings that have hit Damascus in recent weeks amid fierce fighting in the capital's suburbs between Assad's forces and rebels seeking to topple him.

The Syrian Observatory for Human Rights said the explosion was followed by a heavy deployment of security troops in the area on the southern edge of Damascus.

Fox News' Justin Fishel and the Associated Press contributed to this report.