From the folks at Jane's on "Russian TOS-1 and Pantsyr-S1 systems reported in east Ukraine":
If accurate, the reports provide further indication that Russia is becoming less and less concerned with disguising its activities in east Ukraine, because Russia is the only logical source for these systems. Indeed, given the specialist roles of the equipment, it is not unreasonable to believe that the systems are being operated by Russian personnel.
Both systems are among the most modern in Russia's inventories, and neither is in Ukrainian service. Neither system has been particularly widely exported, with none of those customers a likely potential source for the systems. The TOS-1 has only been exported in limited numbers to Azerbaijan, Kazakhstan, and Iraq. Meanwhile, the Pantsyr has only been exported to the Middle East, with orders from Algeria, Iraq, Syria, and the United Arab Emirates.
From a live broadcast:
Russian Foreign Minister Sergei Lavrov accuses Ukrainian government forces of seeking to make gains on the ground against pro-Russian rebels in order to improve Kyiv's position at peace talks on February 11.
Lavrov says Ukraine must agree with rebels if it wants control over its border with Russia in separatist-held areas.
A generous dollop of incredulity via Twitter based on Lavrov's latest remarks on Ukraine: