BEIJING - Following last month's government-initiated anti-monopoly probe, China's two telecommunications giants announced Friday they will substantially raise their broadband speeds while further lowering broadband costs over the next five years.

China Telecom and China Unicom also said that they have sent applications to the National Development and Reform Commission (NDRC) to end the investigations.

The NDRC confirmed Friday it had received the applications, which were sent on November 17. The NDRC said it is addressing the applications in accordance with relevant laws.

The NDRC, the country's top economic planner, said on November 9 that it was investigating the two companies over suspected monopolistic practices in the broadband access business.

China Telecom and China Unicom account for 90 percent of the country's broadband business and have formed a monopoly in the market, an NDRC official previously said on the condition of anonymity.

Li Qing, deputy head of the NDRC's price supervision and anti-monopoly department, said last month that China Telecom and China Unicom did not fully integrate their networks and, therefore, increased access costs and slowed down Internet speeds.

She also noted that the two companies were using their market dominance to practice price discrimination.

In a statement on its website, China Unicom said that it found improper price charges from Internet service providers during its checks following the anti-monopoly probe, and its network was not fully integrated with other networks.

China Unicom said it has submitted a plan to correct its practices to the NDRC. It also pledged to enhance broadband access speeds during the next five years and further lower broadband service charges for the public.

China Telecom also said in an online statement that it found improper charges from Internet service providers, and its network integration with other major networks did not meet regulatory requirements.

It said it will work to fix the problems in a prudent manner, and will work with other major telecommunications operators including China Unicom and China Telecom to fully integrate and inter-connect their networks.

During the next five years, China Telecom will lower broadband service charges by around 35 percent for the public, the online statement said.

According to China's anti-monopoly law, law enforcement authorities can decide to end anti-monopoly investigations if the business operators promise to take concrete actions to correct their practices in a given period approved by the authorities.

The NDRC's probe into the two operators was also the first anti-monopoly case involving large state-owned enterprises in China since the country implemented its first anti-monopoly law in 2008.