BEIJING, May 13 (Xinhuanet) -- China is considering building five major undersea tunnels in the coming 20 to 30 years, including one linking the mainland with Taiwan, an expert revealed here Friday.

    Qian Qihu, an academician with the Chinese Academy of Engineering, told an ongoing Sino-Russian seminar on engineering technology in Beijing that one of the planned cross-straits tunnels was expected to connect east China's Fujian Province with Taiwan. Fujian and Taiwan lie on the opposite sides of the Taiwan Straits.

    The other four tunnels may be established between Hong Kong-Macao-Guangzhou-Shenzhen-Zhuhai, Dalian-Yantai, Shanghai-Ningbo, and Guangdong-Hainan.

    Most of the projects will be constructed beneath the water, but the construction of some bridges is also needed, said the expert, adding that some technical problems involving the handling of rock and soil are yet to be solved.

    China began to build its first undersea tunnel in Xiamen, Fujian this year. Construction of the 9-kilometer tunnel, which has some 6 kilometers under the sea level, is expected to complete in 2010.

    The Chinese mainland and the island province of Taiwan, which were separated for decades as a result of a civil war in the late 1940s, have witnessed increasingly closer economic and trade links over these years. Attaching top priority to national reunification, the Chinese government has proposed many measures for the promotion of the benefits of people on both sides of the Taiwan Straits.