(FoxNews.com) -- Syrian forces have mixed chemical weapons and loaded them into bombs in preparation for possible use on President Bashar Assad's own people, Fox News confirms.
A senior U.S. official told Fox News that bombs were loaded with components of sarin gas, a deadly nerve gas. Syrian forces have 60 days to use these bombs until the chemical mixture expires and has to be destroyed.
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.
The United States has said chemical weapons use would be unacceptable and would trigger greater Western intervention in the conflict.
In Brussels earlier Wednesday, U.S. Secretary of State Hillary 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.
Turkish Foreign Minister Ahmet Davutoglu was quoted Wednesday in the Turkish newspaper Sabah as saying that Syria has about 700 missiles, some of them long-range.
Gunmen loyal to opposite sides in Syria's civil war battled Wednesday in the streets of the Lebanese city of Tripoli. The fighting has killed six people and wounded nearly 60 since Monday, security officials said.
The bloodshed is a sign of just how vulnerable Lebanon is to getting sucked into the Syrian crisis. The countries share a porous border and a complex web of political and sectarian ties that is easily enflamed.
The Lebanese men killed in Syria were Sunni Muslims, like the majority of rebels trying to overthrow Assad's regime. Assad and much of his inner circle belong to the Alawite sect, which is an offshoot of Shiite Islam.
The fighting in Lebanon comes at a time of deep uncertainty in Syria, with rebels battling government troops near Assad's seat of power in Damascus.
Syria has been careful not to confirm it has chemical weapons, while insisting it would never use such weapons against its own people.
But as the regime wobbles, there are fears the crisis will keep spiraling outside its borders. Fighting has spilled over into Turkey, Jordan and Israel since the uprising began more than 20 months ago, but Lebanon is particularly susceptible.
Seventeen times bigger than Lebanon and four times more populous, Syria has long had powerful allies there, including the Iran-backed militant group Hezbollah. For much of the past 30 years, Lebanese have lived under Syrian military and political domination.
Meanwhile, the unrest inside Syria shows no sign of slowing down.
The uprising began with peaceful protests in March 2011 and later escalated into a civil war that the opposition says has killed more than 40,000 people.
Besides the violence roiling the capital, Damascus, there was growing speculation about the fate of a top Syrian spokesman who has become a prominent face of the regime.
Lebanese security officials have said Foreign Ministry spokesman Jihad Makdissi flew Monday from Beirut to London. But it was not clear whether Makdissi had defected, quit his post or been forced out. Syria has had no official comment on Makdissi, who has defended the regime's crackdown on dissent.
Fox News' Justin Fishel and the Associated Press contributed to this report.