(CBS News) LEBANON - The Syrian dictator threatened Monday to use chemical weapons and biological weapons against any aggression from foreign powers. It's the first time Syria admitted it has weapons of mass destruction.
A Syrian government spokesman drew a line, though, saying the dictatorship would not use those weapons against Syrian civilians.
President Obama had a warning for Assad on Monday: "Given the regime's stockpiles of chemical weapons, we will continue to make it clear to Assad and those around him that the world is watching and that they will be held accountable by the international community and the United States should they make the tragic mistake of using those weapons."
Syrian rebels, fighting the 42-year-old Assad dictatorship, have seized the initiative over the last week; a bomb killed Assad's defense minister and three top officials.
The rebels held several Syrian border crossings for a time, and now they're closing in on Syria's second most important city, Aleppo.
The war has now come to Aleppo. Until a few days ago, Syria's biggest city had stayed relatively calm. Not anymore.
A major opposition offensive is under way to take this vital commercial hub.
Syrian Free Army colonel Abdel al-Akaidi made the call to arms online, saying in a video: "We ordered all our forces to move towards Aleppo and liberate the city."
However, so-called liberation comes at a huge cost. Just 30 miles north of Aleppo, in Azaz, rebel fighters are celebrating a hard-won victory. After 100 days of intense fighting, they finally control the town, but many of the buildings are rubble.
Most of the residents had to run for their lives. Syrians, both pro- and anti-regime, know this now: Whenever the Free Syrian Army digs in, it's time to leave, to escape the lethal clashes that follow with government troops.
Wael al-Kaldy is an opposition activist who also works with some of 30,000 Syrians seeking refuge in Lebanon, including these recent arrivals now living in a school.
They fled last week from heavy shelling in Damascus, when rebel fighters took over whole neighborhoods, drawing fire from the Syrian army.
That, said Kaldy, put innocent lives in a crowded city at risk.
"If they want to fight, fight and run. No problem. Don't hide behind civilian, or the buildings of civilian. They will bomb it for sure," Kaldy said.
They, the regime's troops, have bombed situations like that before, hard enough to drive rebel fighters out. As of Monday night, Damascus is back in government hands, at least for now.
Over the last week or so, the tempo of the fighting seems to have increased quite a bit. July is on track to be the bloodiest month yet in this conflict. The Syrian Observatory for Human Rights says 2,752 people have died so far this month alone, a quarter of them government troops. About 19,000 have been killed in the last 17 months of this uprising.