Washington may still impose sanctions over the construction of an underwater natural-gas pipeline between Russia and Germany through the Baltic Sea, U.S. Energy Secretary Rick Perry has said.

Speaking during a visit to Warsaw, Perry told reporters on November 8 that he saw "no signals where we would ever get to the point where we can support Nord Stream 2," the planned 1,230-kilometer project being pushed by the Kremlin.

"Sanctions were an option that [President Donald Trump] maintained," he added.

The United States and Poland, along with the Baltic states and several other EU countries, have expressed concern about the project, which would avoid existing gas pipelines through Ukraine and increase Europe's energy dependence on Russia.

Trump last year signed a law giving him the right to sanction companies involved in Nord Stream 2, which is led by Russian gas giant Gazprom, along with other European investors.

The Kremlin said the move was economically motivated and an attempt to promote U.S. liquefied natural gas (LNG) in Europe.

During Perry's visit to Warsaw, the United States and Poland signed a declaration on November 8 calling for enhanced cooperation on energy security as Warsaw looks to further wean itself off Russian energy supplies.

"Energy security in turn requires energy diversity. That is the reason we oppose the Nord Stream 2 project, which would further increase the dangerous energy dependence many European nations have on the Russian federation," Perry said at a signing ceremony with Polish President Andrzej Duda.

"This is a signal across Europe that this is how your energy future can be developed, the security of the country, the diversity of supply -- this is a great day for Europe," the U.S. energy secretary added.

As part of the 24-year accord, a total of nearly 41 billion cubic meters of U.S. LNG will be delivered from Texas-based Cheniere Marketing International to Poland.

It was the second recent deal struck by the Polish state-run gas firm PGNiG, which sealed a 20-year pact in October with the U.S.-based Venture Global LNG for delivery of up to 2 million tons of LNG a year.

With reporting by AP and Reuters