"Blocking the Nord Stream-2 in itself will not guarantee exports", he stressed.
The $11 billion project is planned to carry 55 billion cubic meters of gas annually 1,230 kilometers under the Baltic Sea from Russian Federation to northern Germany after it becomes operational in early 2020.
During the meeting with German Chancellor Angela Merkel on April 27, Trump offered to refuse from the support of the gas project in the exchange for new trade agreements between the U.S. and the EU.
According to Altmaier, the European Union must ensure that Ukraine will remain a gas even after the new pipeline will be built.
Oudkirk said Washington's objections included past Russian moves to turn off gas supplies to Ukraine and other countries, adding that it would perpetuate "vulnerabilities" in Russian-European ties for another 30 to 40 years.More news: Laurel or Yanny? What science has to say
Earlier, Us officials said that the United Stats may impose sanctions on the companies involved in the implementation of the Nord Stream 2 project.
She said the Baltic was a congested, sensitive military area.
"The new project would permit new technologies to be placed along the pipeline route, and that is a threat", she said.
Oudkirk brushed aside as "false" the suggestion that the U.S.is opposing the pipeline to ensure the USA has Europe as a potential market liquefied natural gas.
"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?"
Denmark is considering passing a law that could block a disputed Russian pipeline project which would run through the North Atlantic Treaty Organisation member's territory due to security concerns. The pipeline, to be built by 2022, is aimed at reducing reliance on Russian gas.