Beijing will extend its subway to the neighboring Hebei province.

According to a plan unveiled by the Standing Committee of Beijing Municipal People's Congress on Thursday, Beijing's subway will link some cities in Hebei province, based on the central government's plan of integrating Beijing, Tianjin and Hebei into a mega urban cluster.

It is the first time that authorities have confirmed the news, but which cities in Hebei will be linked is not specified.

The second phase of Beijing Subway Line 6 will extend further east into Tongzhou District, then its last station Dongxiaoying will be several kilometers from Yanjiao in Hebei.

Yanjiao is also known as a "Sleeping Town" because of its relatively lifeless state during the day. Some 300,000 people commute to work in Beijing and return home to sleep in Yanjiao.

The government of Langfang, Hebei, had hoped that the Daxing Line in Beijing could be extended to its Gu'an county and Yizhuang Line to downtown Langfang.