Ukraine’s President Volodymyr Zelenskiy acknowledged the recording’s authenticity in a report aired by a Ukrainian television channel on Sunday night.

Ukraine will press Iran to hand over the black boxes from the crash of a Ukrainian passenger plane at a meeting with a visiting Iranian delegation on Monday, Foreign Minister Vadym Prystaiko told reporters.

Videos of the protest show what looks to be hundreds of Iranians in front of Amir Kabir University raising their fists, chanting and clapping their hands. A candlelit vigil was held earlier at the university for the victims of the shooting.