(CBS News) There's a vicious fight unfolding in a city of 3 million people -- the largest city in Syria: Aleppo. The Syrian dictatorship is hitting rebels there with attack jets and helicopter gunships. The popular uprising against the 42-year-old dictatorship began about 17 months ago.
There was fresh video Tuesday allegedly showing the city of Homs, where government troops counter attacked rebel forces. It's estimated nearly 20,000 have died in the civil war -- mostly civilians.
A major concern for the world right now is Syria's stockpile of chemical weapons.
Israel has started issuing new gas masks to citizens living close to the Syrian border -- a barometer of the increasing concern over Syria's arsenal of chemical weapons.
Pentagon officials say Syria has the largest operational -- that is, ready for use -- stockpile in the world. Now a spokesman for the Syrian Foreign Ministry has talked openly about using them.
"These weapons are meant to be used only and strictly in the event of external aggression against the Syrian Arab people," said Foreign Ministry spokesman Jihad Makdissi
Besides biological agents such as anthrax, Syria is believed to have hundreds of tons worth of chemical weapons ranging from paralyzing nerve agents like Sarin and VX to old-fashioned blister agents like mustard gas.
They can be launched by missiles, fired by artillery, or dropped from airplanes. It would take more than gas masks to protect against them. A full body suit of the kind worn by American soldiers is needed to prevent Sarin from coming in contact with the skin. There are fears the regime might use these so-called weapons of mass destruction -- WMD, for short -- to put down the uprising, a horrific scenario which the foreign ministry spokesman seemed to rule out.
"Any stocks of WMD or any unconventional weapons that the Syrian Arab Republic possesses would never, would never be used against civilians or against the Syrian people," Makdissi said.
There is also another horrific scenario, in which Syria disintegrates into violence; chemical weapons would fall into the hands of terrorists that might use them against the U.S. or Israel.
The weapons are produced and stored at depots around the country and U.S. officials say they are working with Israel on plans to secure the sites, a mission that would almost certainly require putting troops on the ground.
But for now, both U.S. and Israeli officials say the weapons remain under the control of the Syrian regime, which has actually beefed up security at the storage sites.