Republican presidential front-runner Donald Trump said that if he's elected, he won't launch a preemptive strike on North Korea, arguing that China should use more of its leverage over the communist neighbor.

Trump also claimed that South Korea should pay the United States for "protecting them."

"China should solve that problem and we should put pressure on China to solve the problem," Trump said in an interview with CNN on Wednesday. "If they don't solve that problem, we should be very tough on them on trade -- meaning, start charging them tax or start cutting them off."

Trump again repeated his unfounded criticism that South Korea's getting a defense free ride from the U.S. while paying only "peanuts" for the upkeep of 28,500 American troops stationed in the country to help defend against the North.

"South Korea is a money machine. They pay us peanuts," Trump said. "South Korea should pay us and pay us very substantially for protecting them."

The presence of U.S. troops in South Korea is a legacy of the

1950-53 Korean War, which ended in a truce, not a peace treaty, leaving the divided peninsula still technically at war.

Seoul has long shared the cost of stationing U.S. forces.

Last year, the two countries renewed their cost-sharing agreement, known as the Special Measures Agreement, with Seoul agreeing to pay 920 billion won ($886 million) for the upkeep of the U.S. troops in 2014, a 5.8 percent increase from a year earlier.

Moreover, the American military presence on the peninsula is seen as in line with U.S. national interests in a region marked by a rising China. (Yonhap)