HYDERABAD-At least 20 children were killed and over a dozen were injured on Thursday after a passenger train rammed into their school bus at an unmanned railway crossing in Indian new born state of Telangana's Medak district, officials said. There are apprehensions that the death toll could rise further. The accident occurred at Masaipet in Veldurti mandal of Medak district, about 70 km from Hyderabad, when the bus was taking the students to a private school located at Tupran.There were at least 40 children on the bus belonging to the Kakatiya Techno School. The bus was dragged several hundred meters down the tracks. Mangled remains of the bus and the bodies of the children could be seen near the tracks. The train was travelling from the city of Nanded in Maharashtra to Hyderabad in newly formed neighbouring Telangana state. No one on the train was killed, officials said. "We are investigating the cause of the accident and whose mistake it is," deputy inspector general of police N Suryanaarayana said. The injured were moved to nearby hospitals in Kompally. Telangana chief minister K Chadrasekhara Rao expressed shock over the accident and rushed his ministers to the spot who are overseeing the rescue operations. There are about 14,000 unmanned railway crossings across the country. Accidents at such crossings are common and the Indian Railways said that they happen because of negligence of road users. Railway minister DV Sadananda Gowda had put greater emphasis on passenger safety and security in his maiden budget earlier this month. To ensure passenger safety, funds to the tune of Rs. 40,000 crore would be required to be invested in track renewals, elimination of unmanned level crossings and construction of road under-bridges and over-bridges. For 2014-15, Gowda has allocated Rs. 1,785 crore for the construction of road underbridges and overbridges. Railway officials say this would go a long way in bringing down casualties at level crossings; 40% of all rail casualties occur at unmanned crossings. Indian railway minister had also announced the government's decision to eliminate unmanned level crossings altogether.