EU foreign ministers meeting in Brussels on Monday are expected to trigger new restrictive measures on Russia following the sentencing of dissident Alexei Navalny.
If agreement in principle is struck, as diplomatic sources say is likely, the legal framework and intended targets could be worked out in the coming weeks.
Austrian Foreign Minister Alexander Schallenberg told Germany's Welt newspaper he believes a clear majority will back sanctions. Unanimity is normally required.
These could be asset freezes or travel bans. It is thought the bloc could use its new instrument to punish human rights violations for the first time.
In comments to Welt, Russia's EU ambassador Vladimir Chizhov warned that Moscow would be prepared to respond should the EU choose to move on new sanctions.
After surviving a nerve agent poison attack and receiving treatment in Germany, Navalny returned to Russia in mid-January and was immediately arrested.
Sentenced to prison
The prominent Kremlin critic has since been sentenced to a multi-year prison term on charges of violating parole for a fraud conviction.
On Saturday, the 44-year-old was denied appeal and then later in the day fined a large sum for insulting a World War II veteran.
Together with developments in Belarus, Navalny's case is the latest flashpoint in EU-Russian relations. The bloc already applied sanctions for Moscow's role in the Ukraine conflict, as well as for the anti-corruption campaigner's poisoning.