The government has formally approved Rakuten Inc.'s entry into the country's mobile telecommunications sector with its own wireless network, potentially sparking a price war in an already saturated market.

Internal Affairs and Communications Minister Seiko Noda issued the certificate Monday. The e-commerce giant will start its service in October 2019 in a market currently dominated by NTT Docomo Inc., KDDI Corp. and SoftBank Group Corp.

"I am very happy, and at the same time, am feeling the responsibility (for our latest action)," Rakuten Chairman and CEO Hiroshi Mikitani told reporters after the certificate ceremony.