A multi-billion pound deal in which Cairn Energy agreed to sell up to 51% of its Indian business has been further delayed after being referred to a panel of ministers by the Indian government.
The Edinburgh oil exploration firm agreed last August to sell a majority stake in Cairn India to Vedanta, one of India's largest metals and mining companies.
The deal, which would be the largest in India's oil and gas sector, was estimated to be worth up to £6bn.
Approval has been delayed by a dispute about royalty payments by Cairn India's partner, state-run Oil and Natural Gas Corp.
Cairn Energy, which has a 62.37% stake in Cairn India, recently completed the world's longest heated pipeline to pump oil from its Rajasthan field in India.
At the end of March Cairn Energy announced that profits were up 20-fold since oil started flowing from its Rajasthan field.
The company made US$1.1bn (£674m) in pre-tax profits last year, before extensive exceptionals, compared with US$53m (£32m) in 2009.