Any companies involved were in "an elevated position of sanctions risk", she said. "We would be delighted if the project did not take place".
The US push came a day before Chancellor Angela Merkel travels to Sochi to meet Russian President Vladimir Putin for talks that will touch on Nord Stream 2, as well as the US decision to withdraw from the Iran nuclear deal.
U.S. President Donald Trump has urged Germany to refuse from the support of the construction of the Nord Stream 2 gas pipeline as N-TV reported citing the sources among the officials.
The US stepped up its opposition to the Nord Stream 2 natural gas pipeline linking Russian Federation and Germany, saying the project raises security concerns and that it could draw US sanctions. It is due to go online at the end of next year.
He said Germany viewed Nord Stream 2 as primarily a commercial project, but saw the need to consider the interests of Ukraine as a gas transit country, and of countries in Central and Eastern Europe.
"The new project would permit new technologies to be placed along the pipeline route and that is a threat".
In addition, the United States has threatened to sanction European companies that help build the pipeline.
"Does he agree that there appears to be no economic justification for this, but it is instead a political project created to increase European dependence on Russian gas and to weaken Ukraine and will he press that point on our allies, particularly Germany and Denmark?"
"Germany is not doing anything against the interests of Ukraine".
Merkel sent her economy minister, Peter Altmaier, on a frantic diplomatic trip to Moscow and Kiev this week in an effort to secure a deal that would keep some gas flowing through Ukraine, which now earns up to 2 billion euros a year from transit fees.
According to Altmaier, the European Union must ensure that Ukraine will remain a gas even after the new pipeline will be built.