NTT DoCoMo will make a formal decision at a board meeting on Friday, the sources said.

An NTT DoCoMo spokesman said the company was considering various options for its overseas operations but that nothing had been decided.

Japan's top operator of mobile phone services is expected to book about 80 billion yen in related losses in the financial year ended on March 31, results of which are due to be announced at 3 pm , the sources said.

NTT DoCoMo invested 266.7 billion yen in Tata Teleservices in 2009. The company ranks seventh in India with 63 million subscribers as of the end of March.