Summons to give evidence on the Shehyni border incident at the Polish-Ukraine border will be sent to persons involved on Monday, September 11, Ukraine's Interior Minister Arsen Avakov has said.

"The National Police has opened a criminal investigation. We insist that each of the participants in the event goes to the police to give testimony. If they appear themselves, great. If not, the requisite summons are today being sent to all those involved in the ruckus," Avakov said during a joint meeting with the chief of Ukraine's Border Service on Monday in Kyiv.

Avakov also recommended those who illegally crossed the state border on Sunday, September 10, at the Shehyni border checkpoint to return there in order to pass through customs control.

Avakov emphasized that law-enforcement agencies will follow the law closely.

"The Border Service has appealed to the court agencies in order to establish border violations by Mr. Saakashvili pursuant to Article 204 of the Administrative Code. There may be other infractions. His legal status here, in Ukraine, will also be established," Avakov said.