WASHINGTON, Jan 6 (Reuters) - The U.S. State Department said that a bill being pushed by Republican Senator Ted Cruz to slap sanctions on the Nord Stream 2 natural gas pipeline would undermine the united front in response to Russia, spokesperson Ned Price said on Thursday. "Our concern is that, if passed, the legislation would only serve to undermine unity amongst our European allies at a crucial moment when we need to present a unified front in response to Russian threats against Ukraine," Price told reporters. Cruz struck a deal with Democrats last month to get a vote before Jan. 14 on the Russia-to-Germany natural gas pipeline in exchange for lifting his hold on dozens of Democratic President Joe Biden"s ambassador nominations. Under the deal, Cruz"s bill, which would impose measures on the pipeline under previous mandates, would need 60 votes to pass, a hurdle in the 50-50 Senate, where bipartisanship is scarce. U.S. officials starting Monday are joining three sets of talks involving Russia as Washington tries to dissuade Moscow from invading Ukraine after massing tens of thousands of troops along its border. The Biden administration has opposed the pipeline as it would bypass Ukraine, depriving it of lucrative transit fees. But last year it lifted sanctions on Nord Stream 2 AG, the company that controls the project, as Biden sought to repair relations with Germany and other European allies. The $11 billion pipeline, led by Russia"s state gas company Gazprom , could be approved by German regulators in the middle of the year, the chief executive of Uniper SE (UN01.DE), one of five European energy companies helping to finance the pipeline, said this week. Few Democrats in the Senate are likely to support the Cruz bill, which imposes sanctions within weeks of being signed and allows Congress to vote to reinstate the measures should the president waive them. Senator Jeanne Shaheen, a Democrat who has supported sanctions on Nord Stream 2, called Cruz"s legislation "ill- timed" as Washington should be working closely with Germany and others on potential Russian action in Ukraine, a Politico report said this week. Shaheen and other Democratic senators were leaning against supporting the Cruz bill, the report said. Price said the administration is committed to working with Congress on a strong deterrent against Russian aggression in Ukraine. "Unfortunately this amendment is not, in our estimation, a genuine effort to counter further Russian aggression or to protect Ukraine," he said. Germany, Europe"s biggest economy, has pushed for the pipeline because it needs natural gas as it transitions off coal and nuclear power.