BEIJING -- At first, the footage seems like standard state media fare: a dutiful update on military drills in Inner Mongolia, replete with soldiers, smoke and guns.

But the People's Liberation Army fighters featured in the July 5 clip from China's state broadcaster, CCTV, are not storming sand dunes but a building that bears a striking resemblance to the presidential office in Taipei.

The similarity between the structure in the video and the Taiwanese landmark was pointed out this week by a media outlet in Shanghai that called it proof that China could "use force to solve the Taiwan issue." In a statement to the Wall Street Journal, China's defense ministry flatly denied a link: "This is a routine annual military exercise, and isn’t directed at any particular target.”

Taiwan is not pleased. A spokesperson for the Mainland Affairs Council on Thursday spoke out against the "targeted" drill, promising to express "stern protest" through "proper channels." The Taiwan Ministry of National Defense said the move was unacceptable — to both Taiwan and the world.

There is a lot we don't know about the video. It is still unclear, for instance, if the drill featured a real palace-like target. (In the video, it looks as if it's computer-generated.) The fact that the footage aired on CCTV suggests some level of official approval, but does that mean it's the central government line? (No.)

Still, the fact that a minutes-long clip of unclear origin created such a brouhaha says much about the anxious state of cross-strait ties heading into next year's presidential poll.

Taiwan's current president, Ma Ying-jeou, came to power in 2008 promising to boost ties with China. Over the last seven and a half years, his party, the Kuomintang, or KMT, has focused on bolstering trade, tourism and transport links.

This proved popular with China's ruling Communist Party and, initially, was well received at home. But Ma's fortunes have faded and the relatively China-skeptic opposition, the Democratic Progressive Party (DPP), may well take power in 2016.

While front-runner Tsai Ing-wen has vowed repeatedly to maintain the "cross-strait status quo" if elected, the prospect of a Tsai-led DPP government does not please the People's Republic of China. A PRC official recently warned Tsai against "engaging in any form of 'Taiwan independence' separatist activities."

Given Beijing's worries, some wondered if the footage could signal a return to a more aggressive posture.

"To those of us who have been around since the last time the DPP was in office, this is oddly familiar," said J. Michael Cole, a Taipei-based senior fellow with the University of Nottingham’s China Policy Institute and a senior officer at Tsai’s Thinking Taiwan Foundation.

The last time the DPP was in power, Beijing quite liked to "threaten dire consequences," he said. But "over the past seven or eight years they have stayed away from sending signals that the PLA would be called upon for Taiwan strikes."

Others rejected the idea that the video represents a change in policy — or really much of anything at all. "Cross-strait relations are not intense right now," says Yu Keli, director of Institute of Taiwan Studies at the Chinese Academy of Social Sciences. "We should cultivate a peaceful environment instead of a tense one."

Gu Jinglu in Beijing contributed to this story.

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