European Parliament President Antonio Tajani said he would call on Poland’s prime minister to ensure the safety of MEPs after nationalists hung portraits of six Polish MEPs on mock gallows.

This happened during a recent demonstration in Katowice, southern Poland. Nationalists “hung” the pictures of MEPs who backed a recent European Parliament warning to Warsaw amid concerns in Brussels that the Polish government has eroded the independence of the judiciary and fundamental rights.

As reported by Radio Poland, Justice Minister Zbigniew Ziobro said prosecutors would investigate the mock hangings. Police are analysing video footage of the incident.

Taking to Twitter, Tajani posted: “I will write to [Polish] PM Beata Szydlo to ensure the security of elected Members of the European Parliament to express their opinions independently, without threat and oppose those who spread hatred by exhibiting outrageous pictures of hanged politicians.”