Poland is to declassify nearly all its secret files from the Warsaw Pact, the military alliance of the Soviet bloc which disbanded in 1991, Defense Minister Radoslaw Sikorski said Jan. 3. ”More than 90 percent of the documents will be declassified,” Sikorski told reporters.

Of 1,445 Warsaw Pact files found in Poland’s archives, 441 were not classified military information, and the official secrets status of another 881 will be waived “as of today”, Sikorski said.

The defense minister said he had sought expert advice as to whether another 123 Warsaw Pact documents should also be declassified, and said he expected a reply by the end of the month.

All the documents would be handed to the Polish Institute of National Remembrance (IPN), which houses Poland’s archives.

Historians believe that the files could shed light on the Warsaw Pact intervention to crush a reform movement in Czechoslovakia in 1968 and the declaration of martial law in Poland in 1981.

Signed in the Polish capital in 1955, the Warsaw Pact grouped Moscow and its satellite states of Bulgaria, Czechoslovakia, East Germany, Hungary, Poland and Romania into a military alliance to counter the perceived threat of NATO, the western military alliance.

It was finally dissolved in 1991, when the Soviet Union crumbled.