Republican presidential front-runner Donald Trump on Tuesday denounced the U.S. free trade pact with South Korea as a "disaster" and a "job killing" deal, reinforcing concern about possible negative effects his election could have on the landmark agreement.

Trump made the remark during a campaign stop in Ashburn, Virginia, blaming free trade deals for job losses and other U.S. economic woes, and accusing his Democratic rival, Hillary Clinton, of backing such agreements.

"So listen, since 2000 the number of unemployed people in Virginia has doubled ... Virginia has lost one in three manufacturing jobs since Bill Clinton signed NAFTA," Trump said, referring to the North American Free Trade Agreement. "Signed by Bill Clinton, one of the worst ever, OK.

"Hillary rammed through the job killing trade deal with South Korea in 2011," he said. "That South Korean deal is a disaster for us."

Trump also blasted the 12-nation Trans Pacific Partnership trade deal, saying Clinton had backed the agreement, but now she's changed her position.

"She called it the gold standard, but when she heard me talking about it she said she didn't want it," Trump said, adding that even though she's now expressed reservations about TPP, she will ultimately approve the agreement "with a couple of minor changes."

On Monday, Trump made a similar negative remark about the Korea trade deal during a campaign speech in Columbus, Ohio, in an effort to drum up support in one of the "rust belt" cities with declining economies. He said the Korea agreement "has been a killer" of jobs.

Trump is expected to seek renegotiation of the Korea trade deal if he's elected to the White House. Though he hasn't directly mention such a possibility, aides have long said that the real-estate businessman wants to reevaluate or go back to "ground-zero" with regard to free trade agreements.

The painstakingly negotiated Korea-U.S. FTA has been in effect since 2012 and has widely been considered a symbol of the economic alliance between the two countries. Attempts to revise or renegotiate the agreement could set off diplomatic tensions.

Trump vowed to pull out of the Trans Pacific Partnership if elected president. He also said he would immediately renegotiate NAFTA to get a better deal, and withdraw from the deal unless Canada and Mexico agree to a renegotiation. (Yonhap)