At least 14 school students and two teachers drowned after their boat capsized in the Harni Lake on the outskirts of Vadodara, Gujarat, on Thursday, PTI reported.

They were from a private school and were on a picnic.

The boat, with a carrying capacity of 16 persons, had 34 passengers aboard at the time of the incident, The Indian Express reported, quoting an unidentified police official. While there were 30 students, aged between 12 years to 13 years, the four others were teachers.

Of these, 18 students and two teachers were rescued and one student has been admitted to Sir Sayajirao General Hospital for treatment, PTI reported quoting an unidentified police official.

The National Disaster Response Force said that the rescue operation was being hampered by the sludge accumulated on the lake bed.

The Gujarat home department has ordered the Vadodara district magistrate to investigate the incident and submit a report within 10 days, ascertaining whether the accident wad been caused by negligence, The Indian Express reported.

Panna Momaya, the deputy commissioner of police, told The Indian Express that a first information report has been registered against five persons. They have been booked under Indian Penal Code Sections 304 (culpable homicide not amounting to murder), 308 (attempt to culpable homicide) and 337 (rash or negligent act endangering human life).

Gujarat Chief Minister Bhupendra Patel said that he has instructed the administration in the district to provide immediate relief and treatment to those rescued.

Prime Minister Narendra Modi expressed his condolences to the families of the dead and announced an ex-gratia payment of Rs 50,000 to them.

“Distressed by the loss of lives due to a boat capsizing at the Harni lake in Vadodara,” Modi said in a social media post on Thursday. “My thoughts are with the bereaved families in this hour of grief. May the injured recover soon. The local administration is providing all possible assistance to those affected.”

Congress President Mallikarjun Kharge said that the deaths of the students were heart-rending.

“Many students are still reported missing in this accident,” Kharge said. “Gujarat government and administration are requested to expedite the relief and rescue operations and make every possible effort to save the lives of the students. In this hour of grief, we stand with the bereaved families and express our deepest condolences.”