BERLIN (CNN) - German officials Monday pressured Russia and Ukraine to agree on a new natural gas contract, but also said Germany has 2-1/2 months during which it can find other means to fill any gap caused by the dispute.

The Russian natural gas monopoly Gazprom began Sunday to shut down the flow to Ukraine after the Ukrainian government rejected a Russian compromise that would have delayed a quadruple price hike for three months.

Western Europe, including Germany, is watching the battle anxiously, because the same pipelines that take Russia's gas to Ukraine also feed gas to heat homes in Western Europe, supplying it with more than a quarter of its natural-gas needs.

Germany called on both countries to reach "an acceptable compromise" as soon as possible, government spokesman Thomas Steg told a regular news conference. Germany "expects that Russia and Ukraine fulfill their contracts" and not limit gas deliveries, he added.

Germany has been in contact with both sides in the dispute, but is not mediating, since neither side has requested such a role, Steg said.

Officials also said Germany has 75 days of potential gas sources that could fill any shortfall, including extra gas from Norway.

Asked whether the gas crisis could affect the German-Russian gas pipeline deal reached last year, Steg said that was a private agreement and not a political decision. And asked whether former chancellor Gerhard Schroeder, who has accepted a position at Gazprom, could help end the crisis, Steg said that was up to Schroeder himself.

Ukraine announced last week it had signed an extension of its agreement with Turkmenistan, which supplies about half of Ukraine's natural gas.

Still, experts project that Ukraine will run out of natural gas around the summer.

________________________

For more on the natural gas dispute, click here.