By Christopher Bodeen

Associated Press

BEIJING — U.S. Defense Secretary Jim Mattis, who has accused China of “intimidation and coercion” in the South China Sea, is visiting Beijing this week as the countries increasingly spar over U.S. arms sales to Taiwan and Beijing’s expanding military presence overseas.

Mattis will be the first defense secretary in President Donald Trump’s administration to visit China. His trip highlights the need for the U.S. and its chief rival in East Asia to engage each other despite increasingly stark differences and mutual suspicion.

Mattis’ mission occurs as the Trump administration is set to start taxing $34 billion in Chinese goods in two weeks while Beijing has vowed to retaliate with its own tariffs on U.S. products. The United States appears likely to rely on China for help getting North Korea to deliver on denuclearization promises made at a summit in Singapore between Trump and North Korean leader Kim Jong Un.

Below are some of the thorny issues:

The South China Sea will likely be near the top of the agenda in discussions between Mattis and Chinese officials, with the U.S. issuing threats against Beijing for its continued militarization of the waters. “There are consequences that will continue to come home to roost, so to speak, with China, if they don’t find a way to work more collaboratively with all of the nations who have interests,” Mattis said earlier this month. He said China’s weapons were placed in the region for “intimidation and coercion.” The Pentagon last month withdrew its invitation for China to participate in a large-scale multinational naval exercise in what it called “an initial response” to the militarization of the South China Sea.

China was seen as taking home a major win when Trump announced at the summit with Kim that the U.S. would suspend joint U.S.-South Korea war games the North Korean and Chinese governments have long opposed. Mattis and South Korean leaders were seen as caught off-guard by the decision. U.S. and South Korean officials now see the pledge as helping advance nuclear negotiations with North Korea. China welcomed the move, and Kim met with Chinese President Xi Jinping in Beijing last week but no new measures toward denuclearization have been announced. Trump said last week that “total denuclearization” has “already started taking place.”

China’s complaints about U.S. contacts with Taiwan have grown louder as the U.S. has sought to increase exchanges with the self-ruled island Beijing claims as its territory, and sells more weapons to it. Mattis will likely hear those arguments made even more forcibly after Trump this year signed the Taiwan Travel Act encouraging high-level visits between the two sides, and the Department of Defense agreed to give American contractors marketing licenses for diesel-electric submarine technology sought by Taiwan’s armed forces.