President Donald Trump has requested the United States Trade Representative to identify $200 billion worth of Chinese goods for additional tariffs at a rate of 10 percent.

The new duties will go into effect "if China refuses to change its practices, and also if it insists on going forward with the new tariffs that it has recently announced," the president said in a statement provided by the White House late on Monday.

Beijing has pledged to fight back if Trump goes ahead with the new tariffs.

U.S. stock index futures fell following the news, while Asian equity markets were mixed.

It's the latest development in escalating trade tensions between the world's two largest economies. On Friday, the U.S. announced a 25 percent tariff on up to $50 billion of Chinese products, prompting Chinese President Xi Jinping's administration to respond with a 25 percent tariff on $34 billion of U.S. goods.

"It's one thing to retaliate with $50 billion here and $50 billion there but when the [U.S.] president trots out another $200 billion, that's quite concerning," Max Baucus, former U.S. ambassador to China under President Barack Obama, told CNBC.

"This reminds me little bit of an old western ... If there's a gunfight trade war, somebody's going to get hurt," he continued: "Trump is going to have to find some way to back down and let China save face so that both sides can back down gradually and respectfully."