Singapore Telecommunications Ltd. (Z74.SG) will increase its stake in India's largest mobile phone service provider Bharti Airtel Ltd. (532454.BY) to 31.95% as part of its strategy to maximize the value of its existing business. As part of the agreement, SingTel through its unit Pastel Ltd., will acquire 730,000 shares in Bharti Telecom Ltd. and will pay up to US$654 million for the acquisition, SingTel said in a statement late Friday.