A group of men allegedly assaulted a Swiss couple in Uttar Pradesh’s Fatehpur Sikri near Agra, leaving the man with a fractured skull and impaired hearing and the woman with a broken arm. The police have arrested three minors so far in connection with the case, ANI reported, quoting a police officer.

The police identified one arrested suspect as the brother of Mukul, who had planned the attack. “We have now identified two of the accused... Search is on for Mukul,” Pradeep Kumar, the officer in charge of Fatehpur Sikri police station, told the Hindustan Times.

Additional Director General of Police C Prakash said that the man was arrested from the Rajasthan border, and efforts were on to trace the others, according to ANI.

The incident took place on Sunday afternoon. Kumar said the couple was attacked when they were walking alongside a train track in Fatehpur Sikri. The men attacked the couple with sticks and stones.

External Affairs Minister Sushma Swaraj said she has sought a report from the state government. Ministry of External Affairs officials later met the couple.

Union Tourism Minister Alphons Kannanthanam wrote a letter to Uttar Pradesh Chief Minister Adityanath, saying “speedy action” must be taken to bring the attackers to justice. “I am deeply concerned that two Switzerland citizens were attacked and injured at Fatehpur Sikri,” Alphons said in the letter accessed by News18. “You would kindly appreciate that such incidents negatively impact our image and are detrimental to our efforts in promoting India as a tourism destination.”

“Adityanath is in Agra today, so the inquiry into the incident will be looked into in utmost detail,” Alphons told News18.

Quentin Jeremy Clerc and Marie Droz told The Times of India that the men first began remarking loudly about the couple and then tried to take selfies with Droz. They also tried to find out where the couple was staying in Agra. “They hurled stones at both of us,” Droz told the daily. “I was hit on the back, shoulder and hand. I still cannot understand why they attacked us. They didn’t take any of our valuables.” They added that after the attack passersby filmed videos of them on their mobile phones.

The attack highlights the lack of security for foreign tourists in Agra. Adityanath had said that the Taj Mahal was important for the state’s tourism sector. “It is our priority to provide facilities and safety to tourists there,” he had said.