EU governments have debated a gas price cap for weeks, without reaching agreement. While a majority of EU members support some form of cap, Germany, Denmark and the Netherlands are opposed, citing concerns over security of supply.

In a speech to the European Parliament in Strasbourg, the EU executive chief said she would lay out a roadmap in a letter to the leaders who will gather in Prague from Thursday.

Von der Leyen said the European Union had to ensure individual members did not outbid each other for gas on world markets and drive prices up.

She also said the EU needed to step up its negotiations with trusted partners and look into joint procurement, beginning with gas used to generate electricity.

For gas in general, von der Leyen proposed a temporary solution in the form of a cap until a new EU price index was in place. The main TTF price benchmark was guided by pipeline supply and no longer representative of a market that includes more liquefied natural gas, she said.

"It is a temporary solution until a new EU price index ensuring a better functioning of the market is developed. The Commission has kick-started work on this," she told lawmakers.

Von der Leyen said the energy crisis required exceptional measures, but it was paramount that the EU preserve a level playing field.

The Commission has said it is in talks with Germany about its 200 billion euro ($198.8 billion) support package that critics say threatens to distort competition in the bloc.

Von der Leyen said it should boost its REPowerEu plan to reduce dependence on Russian oil with extra funds.

($1 = 1.0058 euros)

(Reporting by Philip Blenkinsop and Bart Meijer; editing by Barbara Lewis)