Trump also said that Clinton "unleashed a trade war against the American worker when she supported one terrible trade deal after another -- from NAFTA to China to South Korea."

Trump vowed to pull out of the 12-nation Trans Pacific Partnership if elected president. He also said he would immediately renegotiate the North American Free Trade Agreement to get a better deal, and withdraw from the deal unless NAFTA partners agree to a renegotiation.

Trump made no direct mention of renegotiation with the deal with Korea in Tuesday's speech. But Walid Phares, a top foreign policy adviser for Trump, said in an interview with Yonhap New Agency last month that Trump wants to go back to "ground zero" with regard to the trade deal.

In addition, Sen. Jeff Sessions (R-AL), who oversees Trump's foreign policy, has also been strongly critical of the trade deal, claiming that it ended up increasing U.S. trade deficits while bringing little benefits.

Korean officials say that even though the U.S. has a deficit in goods trade, the country has about $10 billion worth of surplus in services trade, and Korea has made more investments in the U.S. than the U.S. did in Korea.

The pact, which went into effect in 2012, has been viewed as an economic alliance between the two countries. (Yonhap)