June 27 (Reuters) - An independent committee of telecom firm Millicom International Cellular's board members confirmed on Thursday it has been in talks with Atlas Investissement over a potential buyout, but said the offer undervalued the company.

French billionaire Xavier Niel's investment vehicle Atlas, which is the top shareholder of Millicom with a 29% stake according to a company filing in May, said last month it was exploring financing options to support an offer price of $24 per common share for the telecom company.

The independent committee said the offer price would "significantly undervalue Millicom and not be in the best interests of Millicom's shareholders".

The committee said it will carefully review any information disclosed by Atlas in connection with its offer and will issue its formal recommendation to Millicom's shareholders.

U.S.-listed shares of Millicom, which provides telecom services in Latin America through its TIGO brand, gained about 29% this year, giving the company a market value of about $4 billion as of last close.

(Reporting by Harshita Mary Varghese; Editing by Krishna Chandra Eluri)