"We have completed laying the offshore section of the Baltic Pipe gas pipeline," officials said in a Twitter message on Thursday.
"On 18 November this year, the last weld on the gas pipeline connecting the coasts of Denmark and Poland was made," the tweet added.
Another post said that more than 22,000 pipes with a nominal diameter of 900 millimetres were used during the construction of the about 275-kilometre-long gas pipeline under the Baltic Sea across the maritime areas of Denmark, Sweden and Poland.
Piotr Naimski, the Polish government's pointman on strategic energy infrastructure, was quoted as saying that "this day brings us significantly closer to achieving the desired secure diversity of supply sources to Poland in 2022."
Meanwhile, Tomasz Stępień, CEO of Poland's natural gas network operator Gaz-System, said that the laying of the gas pipeline on the seabed was the most challenging part of the Baltic Pipe project "from an organisational and technical point of view."
"We completed this stage in accordance with earlier declarations and the planned schedule," Stępień added, according to a tweet.
The pipeline, which is part of Warsaw’s efforts to diversify gas supplies and reduce the country’s energy dependence on Russia, last month made landfall in Denmark after previously reaching the Polish Baltic coast, according to officials.
The Baltic Pipe is due to be launched in October next year to operate at an initial capacity of 2 to 3 billion cubic metres per year, and at full capacity from the end of 2022.
It is ultimately expected to have the capacity to carry 10 billion cubic metres of natural gas from Norway to Poland via Denmark annually.
Poland’s annual gas usage is estimated at around 20 billion cubic metres, the bulk of which is imported from Russia’s gas giant Gazprom under a contract expiring in December 2022.
Naimski reaffirmed in September that Poland would stop buying Russian gas after its long-term supply deal with Gazprom expires at the end of next year.
President Andrzej Duda in 2019 described the Baltic Pipe as “a strategic project for Poland’s energy transformation, as well as for the energy security of the entire Central and Eastern Europe region.”