The Western allies operate a 10,000-kilometre (6,250-mile) network of European pipelines, bringing fuel and lubricants for tanks and aircraft to where troops might need them in time of war.

But the system was set up during the Cold War, when Poland was still a member of the opposing Warsaw Pact, and NATO's pipelines still do not reach its bases closer to the borders with Russia and Belarus.

Poland has been considering joining the NATO Pipeline System (NPS) for many years and on Friday the defence ministry and national pipeline operator PERN unveiled a 4.7-billion-euro plan to do so.

"This is one of the largest investments in the security of the Polish state in the last 30 years," deputy defence minister Cezary Tomczyk told reporters at the signing ceremony.

Warsaw, the minister said, plans to build a 300-kilometre pipeline from Germany to its military base in Bydgoszcz, in north-central Poland and home to NATO's "joint force training centre" and several support units.

The alliance has helped fund the studies underlying the planning of the extension, but Poland and PERN will build and operate their section of the project once all 32 allies give the go-ahead.

Poland is NATO's leading military spender in terms of proportion of GDP assigned to military and security programmes and a staunch ally of neighbouring Ukraine, which suffered an all-out Russian invasion in February 2022.

Last month Poland was among the NATO members rattled by a flurry of alleged Russian drone incursions into allied air space.