India on Thursday condemned an alleged act of vandalism at its embassy in Zagreb as Croatia promised to prosecute the offenders.

The Indian foreign ministry said that an act of “trespassing and vandalism” at its embassy in the Croatian capital was committed by “anti-India elements” without providing further details of the incident.

“We have taken up the matter strongly with Croatian authorities and asked them to hold the perpetrators accountable for their reprehensible and illegal actions,” a ministry statement said.

Indian media reported that a video had been posted online, purporting to show Khalistan activists removing the Indian flag and replacing it with the yellow flag representing the Sikh separatist movement.

AFP could not verify the video, while police and the embassy did not immediately respond to questions.

The Khalistan movement seeks an independent state for the religious minority carved out of Indian territory.

The Croatian foreign ministry strongly condemned the incident and added that the interior ministry was pursuing the perpetrators.

“Any violation of the inviolability of diplomatic missions is unacceptable and contrary to international law,” the ministry said in a statement on social media.