The writedown is a non-cash item that will be recognised in Sistema's fourth-quarter results, eroding earnings, one of the sources told Reuters. Sistema declined to comment.

Around half of the writedown is related to a licence revaluation and the rest to goodwill, the Vedomosti newspaper quoted a source as saying.

The Supreme Court of India in February ordered the cancellation of 122 telecoms licences held by eight operators, including Sistema and Norway's Telenor, over alleged irregularities in the way they were awarded in 2008.

Telenor said, last month, it would seek compensation from India, while Sistema asked India to settle the dispute within six months while saying it reserved the right to approach an international tribunal