The Archaeological Survey of India has ordered an investigation into an incident where a group of students from Manipur was allegedly stopped from entering the Taj Mahal on Sunday. An investigation was ordered on Monday into allegations that the Central Industrial Security Force personnel asked for proof of nationality from the students, who were later allowed entry after the local police intervened.

The students had lodged a formal complaint with the ASI after the incident. They said the security personnel told them that they “resembled foreigners”, and were trying to pass off as Indians so that they could pay less for entry. Entry tickets for foreign nationals are for Rs 1,000 per person, while the same for an Indian is Rs 40.

The students from Imphal’s Central Agricultural University were visiting the Taj Mahal as part of their all-India educational trip. The security personnel refused to let them enter even when they showed their ID cards and a letter from the college stating that they were on an educational tour.

The complainants said they were also asked to show Aadhaar cards and only those who had them were allowed to enter the monument. At this point, an argument ensued between the CISF men and a professor, who was travelling with the group. The rest of the students were allowed entry only after the tourism police intervened. “The students alleged that CISF personnel misbehaved with them and that they were asked to show their nationality proof. They then called the tourism police, who reached the spot and intervened to allow the students to enter,” said RP Pandey, SHO of the tourism police station, told The Indian Express.

The ASI confirmed that an investigation has been ordered into the incident and said that they have also asked the CISF to submit the footage from the CCTV at the entry points to the monument.