A group of 77 pilgrims from the Isha Foundation remain missing after a massive flash flood struck areas near the China-Nepal border, killing hundreds and leaving thousands missing.The flash flood struck Gyirong Township in the Tibet Autonomous Region on Wednesday morning, sweeping through villages and towns near the China-Nepal border. It killed three people in Tibet and 359 in Nepal, while hundreds remain missing.The 77-member group, led by Isha Foundation, an organisation founded by Indian spiritual leader Jaggi Vasudev, Sadhguru, has remained out of contact.The Isha Foundation organises multiple Kailash Mansarovar pilgrimages each season. Groups travel from Kathmandu through Nepal to Tibet, with trekking on foot as part of the pilgrimage.In a message posted on his official Facebook page on Wednesday, Sadhguru said one of his Kailash pilgrimage groups was caught in the flash flood while returning to Nepal.The group was at the immigration office in Gyirong when the flood struck, reportedly inundating the building and much of the town. Three volunteers were stuck in Timure, Nepal, he said.Sadhguru said there was no official information on the whereabouts of those missing at the immigration office.The Nepal government has said the entire staff of that particular immigration centre are out of contact.The missing pilgrims include 22 from the US, 12 from Canada, 11 from Australia, nine from the UK, four from Germany, three each from France and Nepal, two each from the Netherlands, New Zealand, Singapore and Spain, and one each from Finland, Hungary, Israel, Lithuania, the Philippines, Portugal, Russia and South Africa.”We are working with the authorities to see if we can get to the location and stand ready to be part of the rescue efforts, regardless of the risk involved,” Sadhguru wrote.He said 21 groups were part of the pilgrimage, of which 495 people have returned safely, while 743 are currently in Tibet and 148 in Nepal.Sadhguru said he was personally in the region and that rescue efforts were under way.However, Nepal Tourism Board officials said they had no information about the matter and were trying to verify it.