According to the Police Department, the Columns of Gediminas, one of the earliest symbols of Lithuania, were painted on both sides of the tombstone. The signs were discovered by the chairman of a society tending to graves in the cemetery at around 1 PM on Sunday.
No suspects have been found yet.
Pilsudski is credited for his contribution to restoring an independent state of Poland after World War I, but he's a controversial figure in Lithuania as he annexed Vilnius Region from Lithuania in 1922.
Lithuania's police have launched a pre-trial investigation into the act of vandalism.
"A pre-trial investigation based on Part I of Article 312 of the Penal Code, i. e., desecration of a grave or another place of public respect, has been started. Since a pre-trial investigation has been launched, more information can be provided only from the prosecutor in charge of the case," Dalia Petrauskienė, spokeswoman of Vilnius Chief Police Commissariat, told BNS on Monday.
Vandals face a jail term of up to one year.
No suspects have been found yet, Audronė Šukienė, prosecutor of Vilnius Regional Prosecutor's Office, told BNS.
PM condemns vandalism
Lithuanian Prime Minister Andrius Kubilius condemned the incident on Monday.
"I strongly condemn such an act of vandalism. Incitement of hatred must be stopped, no matter who does that. I hope that law enforcement institutions will find the guilty and they will be duly punished," the prime minister said in a statement.
Speaker of the Parliament, Irena Degutienė, said she condemned all acts of vandalism not only disturbing the stillness of the dead but also inciting discord among nations by using symbols important for the Lithuanian nation and its history.