Russia's decision to cut off gas supplies to Bulgaria and Poland has shaken the energy market and led to large price increases.
On Monday evening, the EU held an extraordinary meeting on gas supply.
After the meeting, EU Energy Commissioner Kadri Simson warned that Russian gas supplies could be stifled for more people and that "any state could be next", reports the BBC.
Simson spoke after Monday's meeting of EU energy ministers.
Dependence on Russian gas
Many EU countries are dependent on imports of Russian gas - which Russia is trying to take advantage of in an attempt to revive the heavily sanctioned economy.
Russia has demanded payment in rubles for gas supplies - but all such arrangements are contrary to the sanctions, according to the European Commission.
"Fill up before winter"
The uncertain situation regarding gas has led the European Commission to urge member states to increase preparedness.
- As it looks now, most will be able to replenish their gas reserves to about 80 percent by November, says Khashayar Farmanbar (S) to TT after today's EU meeting.
At the meeting, where no formal decisions were made, Sweden stated, among other things, that Russian oil and gas should be originated, Farmanbar states.
- Today we can not see when we get a gas delivery to Sweden how much of what comes from Russia and other countries, he says to SVT News.