President Vladimir Putin's ruling United Russia won a large majority against token opposition, with no party contesting Moscow's war against Ukraine allowed to run. 

"The so-called Duma elections marked another major setback for Russian democracy. Their outcome was never in doubt," Kallas wrote on X.

"The Kremlin silenced dissent, barred the only registered party that opposed its war in Ukraine, and shut out international election monitors. The veneer of democracy is all that remains in Russia."

Kallas said she had "proposed measures against those facilitating these sham elections in occupied Ukrainian territories".

The EU has already sanctioned some 3,000 officials and entities over the war on Ukraine, including Putin. 

The 27-nation bloc last week pushed back a deadline for prolonging its asset freezes and visa bans on some 3,000 individuals and entities to midnight Tuesday (2200 GMT Tuesday).

Ambassadors in Brussels were set to meet for talks on Monday afternoon after failing to make a breakthrough in the morning.

All EU countries are required to agree to extend the sanctions -- a key part of the bloc's response to Russia's war since 2022 -- every six months.

This time around an agreement has been held up as France has joined Slovakia in calling for Russian-Uzbek billionaire Usmanov to be removed from the blacklist.

Officials in Paris have cited "national security" concerns for the request, but refused publicly to give details.

The Financial Times has reported that the demand is linked to a potential prisoner release deal involving French nationals held in Azerbaijan.

Ukrainian Foreign Minister Andriy Sybiga on Monday slammed as "unacceptable" a move to remove two Russian oligarchs from the European Union's sanctions list, adding it would send Moscow a "wrong signal".

"Delisting is unacceptable and would send the wrong signal to Moscow at a time when pressure needs to increase. On the contrary, sanctions need to be tightened," Sybiga said on social media.

More hawkish EU countries -- including Poland and Baltic states -- are fiercely opposed to easing the sanctions on Usmanov for political reasons.

Meanwhile, diplomats said that Luxembourg is insisting that if Usmanov is taken off the list, it wants to see sanctions lifted on another Russian tycoon, Mikhail Fridman.

A diplomat, speaking on condition of anonymity, said a compromise deal on the table would see Usmanov and Fridman removed, and the rest of the sanctions extended for up to 36 months.

Multiple EU diplomats insisted that despite the standoff over Umanov, there was widespread agreement that the EU sanctions should not be allowed to lapse.

The blacklist includes key figures such as Russian President Vladimir Putin and Foreign Minister Sergei Lavrov.