European Union (EU) countries approved a weakened emergency plan to curb their gas demand on Tuesday, after striking compromise deals to limit cuts for some countries, as they brace for further Russian reductions in supply.

Europe faces an increased gas squeeze from Wednesday, when Russia's Gazprom has said it would cut flows through the Nord Stream 1 pipeline to Germany to a fifth of its capacity.

With a dozen EU countries already facing reduced Russian supplies, Brussels is urging member states to save gas and store it for winter for fear Russia will completely cut off gas flows.

Energy ministers approved a proposal for all EU countries to voluntarily cut gas use by 15 percent from August to March.

The cuts could be made binding in a supply emergency, but countries agreed to exempt numerous countries and industries, after some governments had resisted the EU's original proposal to impose a binding 15 percent cut on every country.

Hungary was the only country that opposed the deal, two EU officials said.

The EU deal would exempt from the binding 15 percent gas cut countries such as Ireland and Malta that are not connected to other EU countries' gas networks.

News of the latest reduction to Russian supply has driven gas prices higher, adding to the cost of filling storage, while creating incentives to use less.

Early on Tuesday, the benchmark front-month Dutch contract rose almost 10 percent and is more than 450 percent higher than a year ago.

Countries that meet an EU target for filling gas storage by August could face weaker targets – softening the cuts for roughly a dozen states, including Germany and Italy, based on current storage levels.

They can also exempt the gas they use in critical industries, such as energy-intensive steelmaking, from the target.

In addition, those with a limited ability to export gas to other EU countries can request a lower target, provided they export what they can. That could include Spain, which does not rely on Russian gas, and has said cutting its own demand would not help other countries since it lacks the infrastructure capacity to share spare fuel.

The EU plan has tested countries' solidarity, with Greece and Poland among the countries opposed to mandatory gas cuts.

Some EU diplomats have raised concerns that the number of opt-outs in the final regulation may mean it fails to ensure countries save enough gas for winter.

Although governments including Germany, Europe's biggest gas user, have upped their energy saving measures, EU countries have reduced their combined gas use by only 5 percent, despite months of soaring prices and dwindling Russian supplies.