"That means that any pipeline project, and there are multiple pipeline projects in the world that are potentially covered, is at an elevated sanctions risk", Bloomberg cited Oudkirk as saying.
Her comments came one day before German Chancellor Angela Merkel is due to meet with Russian President Vladimir Putin in the Russian resort of Sochi.
About it reports the German edition of N-TV with reference to the representatives of the governments of the USA, Germany and the EU.
America has warned that Moscow could use an $11 billion gas pipeline project between Germany and Russian Federation to spy in the Baltic Sea.
Altmaier has said he is optimistic that a "substantial" amount of gas will flow through Ukraine in the future.
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.
She also noted that the U.S. Congress has given Trump the power to impose sanctions on a number of Russian energy projects, and companies involved in such projects carry the risk of incurring U.S. sanctions. Up to now Turkey received Russian gas transited via Ukraine, Romania and Bulgaria.
Deutsche Welle however points out that the White House also has an ulterior motive in this matter as it "would like to export to Europe the natural gas it extracts through hydraulic fracking, pushing Gazprom out of the market".
Altmaier, however, attributed United States opposition to its desire to increase its own shale gas exports.
The Nord Stream 2 project has said it will tap banks for financing in the fourth quarter of 2018 or early next year.
Oudkirk said Washington supported the planned Danish-Polish Baltic Pipe because it would diversify sources and routes.
Nord Stream said Germany and Finland have granted all the necessary permits for the construction and operation of the pipeline.