About 200 Bearded Vultures have been spotted in a remote part of India's Himachal Pradesh state, reports say.
State chief conservator of forests Vinay Tandon said the reported sighting was being checked by wildlife officials and would be "hugely significant".
Lammergeiers have been seen on India's border with China, but not in such a large group or at so high an altitude.There has been growing concern in India over the fast dwindling population of vultures in recent years.
Experts estimate there are only a few hundred vultures left in India.
'Pleased'
Mr Tandon said four out of the five major vulture species in India are critically endangered.
"We had reports on Monday that what appears to be a very large colony of Bearded Vultures - or Lammergeiers - were spotted close to the border with China in what is known as the trans-Himalayan region," he told the BBC.
"As yet we are not able to confirm that the birds belong to this species. A team from the state's wildlife department will be making its way to the area as soon as possible.
"We are especially pleased to hear of such a large colony when in recent years the vulture population of India has been disappearing so rapidly."
Mr Tandon said that the vultures had been spotted in Lahaul-Spiti, one of the remotest districts of Himachal Pradesh.
Lammergeiers are long-winged vultures known for their unusual habit of dropping bones on to rocks to smash them open and get at the marrow.
Their world population is estimated at between 2,000-10,000 individuals.
Cattle link
South Asia's vulture population has been virtually wiped out in recent years.
Experts believe vultures have been badly affected by the use of the painkiller diclofenac in cattle.
Vultures feeding on the cattle lose their ability to reproduce.
While Bearded Vultures are not thought to have been so badly affected by the drug, their numbers have nevertheless significantly dwindled in India.
In August conservationists announced that the endangered Slender Billed vulture had twice been successfully bred in the states of Haryana and West Bengal.
Conservationists say that despite the recent sightings, urgent action is still needed to save vultures from extinction in the wild.
"With extinction in the wild likely in the next 10 years, we do not have a moment to waste. The more vultures that we can bring into captivity means a better chance of survival for these rapidly declining species," Birdlife International spokesman Chris Bowden said.