BEIJING, Oct. 30 (Xinhua) -- China's centrally-administered state-owned enterprises (SOEs) have actively participated in the Belt and Road development, undertaking over 3,000 projects in the past five years, a senior official said Tuesday.

"The firms have engaged in the construction of railways, ports, highways, communications networks and other infrastructure projects in countries and regions along the Belt and Road," said Weng Jieming, deputy head of the State-owned Assets Supervision and Administration Commission, at a press briefing.

"In energy and resource areas, the companies cooperated on more than 60 projects on oil and natural gas exploration in over 20 countries, in line with the countries' demands for economic development."

The central SOEs also invested in a large number of industrial and manufacturing projects to help local economies upgrade.

"The companies played a positive role in improving local people's livelihood," Weng said. "About 85 percent of the employees at the central SOEs' overseas branches are hired locally."

"The firms will continue to optimize their models of business cooperation, based on mutual benefits, sound planning and risk controls.

"They will also strengthen cooperation with Chinese private firms, local firms in countries along the Belt and Road, and international corporations to better guard against risks."

As of the end of 2017, central SOEs had more than 7 trillion yuan (about 1 trillion U.S. dollars) of overseas assets in total, with their overseas units realizing 4.7 trillion yuan in revenues and 106.4 billion yuan in profits annually.