The museum houses a huge collection of art and historical items, and has played home for Polish exiles.
Poland's Sejm (lower house) passed a law on Thursday empowering the president to ratify a Polish-American military cooperation agreement, which foresees an increase in the number of US soldiers stationed in Poland.
Up to 80 Polish soldiers will join a NATO mission in Turkey under a decision signed by President Andrzej Duda, head of the National Security Bureau (BBN) Paweł Soloch said on Wednesday.
The graves contain bodies of soldiers killed in battles between the Austro-Hungarian and Russian empires.
Defence Minister Mariusz Blaszczak on Thursday decorated Polish soldiers distinguished in lifesaving and rescue operations. The decorations were part of centenary observations of the 1920 Battle of Warsaw, in which Polish forces halted a Europe-advancing Red Army.
US forces will remain in Poland regardless of who is US president, as guaranteed by Poland's Enhanced Defence Cooperation Agreement with the US, Defence Minister Mariusz Blaszczak said on Thursday on Polish Radio.
President Andrzej Duda has said that the presence of US forces in Poland is worth the sensible, honest and above all fair price that was negotiated.
An agreement on the presence of US soldiers in Poland is to be signed on August 15, Polish Army Day and the centenary of the Battle of Warsaw, in which Polish forces defeated Soviet troops, the daily Dziennik Gazeta Prawna reported on Monday.
The US corps command in Poland will be the most important US command on the eastern flank of NATO, and this is a great achievement, Minister of Defence Mariusz Blaszczak has said.
As there were at least a few countries interested in receiving US soldiers, including Poland, it was important for Poland to discuss this first, said President Andrzej Duda, who met with US President Donald Trump at the White House on Wednesday.