Denmark’s Energy Agency (DEA) has approved the Gazprom-led Nord Stream 2 consortium to lay its natural gas pipeline on the Danish continental shelf southeast of Bornholm in the Baltic Sea, the last remaining hurdle for the controversial project to reach completion.

The DEA said on Wednesday Denmark was "obliged to allow the construction of transit pipelines" under the United Nations Convention on the Law of the Sea.

Most of the 759-mile (1,221 kilometer) undersea pipeline has already been laid. Once completed, Nord Stream 2 would double the original pipeline’s capacity of 55 billion cubic meters/year. In early October, Russian President Vladimir Putin said even if Denmark were to block the pipeline’s transit, it still would be completed by rerouting a segment.

Nord Stream 2, based in Zug, Switzerland, said preparatory work for the Danish segment of the pipeline, spanning 91 miles (147 kilometers), "will start in the coming weeks."

The DEA disclosure brought immediate backlash from U.S. lawmakers. “Time is running out to stop Nord Stream 2,” GOP Sen. Ted Cruz of Texas said Wednesday on Twitter. “In a few short months, Russia will have completed its natural gas pipeline -- putting Putin in a position to further expand his military, exploit our European allies and threaten U.S. energy security.”

The United States has opposed the building of gas conduit since its inception because of energy security concerns on the European continent. During a North Atlantic Treaty Organization (NATO) meeting in July 2018, President Trump said Germany "is totally controlled by Russia because they will be getting from 60-70% of their energy from Russia," and called Nord Stream 2 "a very bad thing for NATO." When Trump appeared alongside Putin days later, he said the United States  "will be competing" against the pipeline as more liquefied natural gas (LNG) was exported to Europe.

Russia remains the largest gas supplier to Europe, but U.S. LNG is on a collision course of sorts with Nord Stream 2 and the Turkish Stream (TurkStream) gas pipeline to move more supply to Western Europe.

In recent months, the Trump administration threatened sanctions against companies involved Nord Stream 2. Russian Energy Minister Alexander Novak in early October called out an administration claim that U.S. gas exports to the European Union (EU) were “freedom gas,” and said instead they were “purely protectionism.”

Nord Stream would bypass existing land routes over Ukraine, Poland and Belarus. Ukraine, which has argued that it would lose revenue because of the pipeline, tried to form a consortium of EU-based companies to stop the new pipeline, but those plans never materialized.

Last March, Germany authorized the project, which is set to enter service by the end of 2020, connecting the Russian port of Ust-Luga, near St. Petersburg, to Greifswald in northeastern Germany.

Some German politicians have also voiced opposition over the pipeline. In early September, in an opinion piece written for Die Welt, German Parliament President Wolfgang Schäuble said construction of the pipeline had destroyed confidence among the country’s neighbors.

“Overlooking the views of our eastern neighbors is not one of the highlights of German politics and has destroyed much trust,” he wrote. “We all bear responsibility for a common Europe, in Berlin and Paris, as well as in Warsaw and Budapest.”

Germany plans to build at least four LNG import terminals by 2023 to help diversify its supply from decades-long reliance on Russian gas. The United States and Qatar, the world’s leading LNG producer, are keen on locking in mid- and long-term LNG offtake deals with German companies.