It is hardly unexpected of Putin.
All the evidence does point to Assad's forces using those weapons:
The munitions - unguided rockets - are the key element in this report. Samples of sarin were recovered from the majority of fragments of the warheads.
But more importantly the two types of rocket used - a Russian-supplied 140mm system and especially the larger 330mm weapon of unknown origin - are significant since according to both Human Rights Watch and a number of independent arms experts - these are weapons that have only been observed in use by Syrian government forces during this conflict.
There is significantly more detail on these weapons in the Human Rights Watch report Attacks on Ghouta (caution: disturbing images) published earlier this month.
And
Putin's stance gets even more ridiculous.
The Syria disarmament plan was unveiled by the US and Russia last weekend.
The West wants the deal enshrined in a UN resolution backed by the threat of military force, but Russia objects.
I doubt the plan to have him destroy his chemical weapons stock is going to work. Assad cannot be trusted and Russia will object and veto any plan to punish him through the UN if he fails to deliver on his promises.
"Assad: Syria needs one year to destroy chemical weapons" from link ^^above^^ : "Putin's stance gets even more ridiculous." -http://www.bbc.co.uk/news/world-middle-east-24155674
Chemical weapons are evidently fairly hard to destroy :
link -
http://www.theguardian.com/world/2013/sep/11/us-syria-chemical-weapons-destruction
"US struggles show hazards of chemical weapons destruction"
"If the Obama administration wants an example of the difficulties involved in destroying chemical weapons, it might reflect upon its own struggles to get rid of cold-war era chemical arsenals stockpiled in tightly controlled storage facilities in Kentucky and Colorado.
The United States promised, but failed, to destroy these stocks by 2012 at the very latest. The most recent forecast from the US is that the process of "neutralising" the chemicals in its Colorado weapons dump will be finished by 2018; the date for Kentucky is 2023. That will be 11 years after the US promised to destroy its chemical weapons stockpiles, and eight years after Russia – the other major possessor of declared chemical weapons – says it will have finished destroying its arsenal.
Since the late 1990s, the US has made great efforts to destroy its own chemical weapons caches, and facilitating the process in the handful of other so-called "possessor states" – in some cases helping fund the process through aid.
However, technological and political challenges have resulted in lengthy delays. By missing its deadlines, the US and other countries have arguably breached a founding principle of the same treaty cited as a reason to justify an attack on Syria.
When the convention came into force in 1997, participating countries agreed to destroy their stockpiles within 10 years, with an option to apply for a five-year extension. Five countries – the US, Russia, South Korea, India and Albania – all missed the main 2007 deadline.
Two years ago, the United States, Russia and Libya were granted further extensions to a previously agreed final deadline for destroying their weapons." - quoted from link at top of quote
Personally, I only know what happens when they are not properly destroyed - over real quick - but lots of "Blowback" or "Unintended Consequences"!! (think GWS)
p.s. There may be other major possessors of "undeclared chemical weapons" and/or under the convention, the nations do not have to destroy "their undeclared chemical weapons"!