The recently opened Danjiang Bridge that spans the mouth of the Tamsui River was the stage for the night-time exercise held on the second day of Taiwan's annual "Han Kuang" military drills.China claims Taiwan is part of its territory and has threatened to use force to seize the island of 23 million people.If China's military, known as the People's Liberation Army (PLA), were to launch an invasion of Taiwan, military experts believe its troops could potentially land on beaches on either side of the Tamsui River and cross the Danjiang Bridge to join forces. "Once the PLA controls the Danjiang Bridge and both sides of the Tamsui River estuary, that would also mean its troops could advance along both banks of the river," Chieh Chung, an expert on Taiwan's defence policy at Tamkang University, told AFP."The goal is simply to prevent the PLA forces from controlling this section of the river, because once they control this stretch of the river, the two landing bases will effectively be linked as one," he said.To stop them in their tracks, Taiwan's military practised blocking the bridge in an hours-long drill that was to end Friday morning before peak-hour traffic.Working under the bridge's blue lights, dozens of Taiwanese army combat engineers assisted by cranes and trucks set up layers of concrete and steel barriers, barbed wire and Hesco walls along the nearly one-kilometre-long bridge.