WARSAW, Poland (AP) — Poland is investing about $2.5 billion to step up security and deterrence on its border with Russia and its ally Belarus, the prime minister said Saturday.

Donald Tusk said work on the Shield-East project which includes building proper military fortifications has already begun. Poland is on the eastern flank of NATO and of the European Union and Tusk stressed it bears additional responsibility for Europe’s security.

“We have taken the decision to invest into our safety and first of all, into a safe eastern border, some 10 billion zlotys ($2.5 billion),” Tusk said.

“We are opening a great project of the construction of a safe border, including a system of fortifications and of the shaping of terrain, (of) environmental decisions that will make this border impenetrable by a potential enemy,” Tusk said.

“We have begun these works, to make Poland’s border a safe one in times of peace, and impenetrable for an enemy in times of war,” he added.