Beijing-Tianjin-Hebei integrated development will enter the period of tackling the difficulties after the previous four years of planning and foundation, said a senior official on Thursday.

Cong Liang, secretary-general of the National Development and Reform Commission, said during the "Beijing-Tianjin-Hebei integrated development forum" held in Beijing that the commission will focus on several tasks in the coming years.

"In the next step, we will actively move out the non-capital functions from Beijing. Meanwhile, we will continue the high-level and high-quality construction of Xiongan New Area," he said. "The construction of Beijing's sub-city center will also be accelerated with high-quality standards."

The other two tasks are strengthening the environmental protection and infrastructure construction in the area, especially in the transportation unit, he said.

Zhang Gong, executive vice-mayor of Beijing, said during the forum that the capital will strictly cap the city's population and construction growth at a certain level for a better development.

"We will solve the big city diseases and build the sub-city center with high standards," he said.

According to Zhao Lei, acting chief executive of Tongzhou district where Beijing's sub-city center is located, Beijing has invested more than 200 billion yuan ($29.5 billion) in the construction projects in the sub-city center in the past two years.

The forum was organized by People's Daily and more than 300 people from 50 departments from Beijing, Tianjin and Hebei, as well as business leaders, scholars and media, attended the event.

At the forum, People's Daily think tank for the regional integrated development was founded.