Search and rescue efforts have begun in the northern regions of the Himalayas after a magnitude 6.8 earthquake hit the area on Sunday. Approximately 53 were killed, said officials, specifically citing 40 dead in India, seven in Tibet and six in Nepal. Thousands more have been injured or displaced.

Most of the damage occurred in Sikkim, where mudslides due to the earthquake made it hard for rescue workers to locate victims.

“We also cannot assess the damage because many areas are inaccessible,” A.C. Negi, a police officer, said to the New York Times. “We are trying our best.”

According to R. K. Singh, two medical teams have arrived in Sikkim via helicopter. They found 10 workers dead at a power plant on the Teesta River.

Nepal’s capital city, Katmandu, suffered death and damages from the quake, as well as other areas in the country. Laxmi Prasad Bastola, an official at the National Emergency Operation Center, said to the New York Times that reports of dead and injured citizens are still “trickling in,” meaning that the death toll could rise.

“This toll can go up, as there are 24 seriously injured people,” said Bastola.