"This is a good time with the fifth anniversary coming up to take a look at KORUS-FTA," Feulner said in the interview held Tuesday. "Review between counterpart organizations in Washington and in Seoul is appropriate and if in fact then there are disputes then that means a renegotiation, I don't see any problem with that. I think there's enough goodwill on both sides that it could be redone."

During the campaign, Trump blamed free trade deals for being a key cause of job losses and other American economic problems in an attempt to woo voters struggling with economic difficulties. Since taking office, Trump also made protection of American workers and companies from foreign competitors his No. 1 priority.

Last month, Trump withdrew the US from the 12-nation free trade deal Trans Pacific Partnership and has stepped up attacks the North American Free Trade Agreement, spurring concern that his next target could be the pact with Korea that he denounced as a job-killing deal during the campaign.

The Korea deal, which went into effect in 2012 after many years of tough negotiations, has been viewed as a symbol of the economic alliance between the two countries. Attempts to revise or renegotiate the agreement could set off diplomatic tensions.

Trump claimed during the campaign that the pact ended up increasing US imports from the South while failing to increase exports. But experts say the US has enjoyed surpluses in services trade under the deal, and US deficits in goods trade would have been larger had it not been for the pact.

Feulner, who is considered a top candidate for Trump's ambassador to South Korea, stressed that a review is necessary because "some of the structures we put in place are not maybe being followed as well as they should be" and because the agreements needs to be updated to reflect fast-moving technology.

"Is intellectual property from the United States being respected in Korea? Patents, trademarks, very sophisticated arguments in terms of high-tech items. How are they being treated on the other side?" Feulner said.

"Technology is moving so fast, why should Korea have a block on Uber, which is a big technology from the United States?" he said, referring to the global online taxi service. "Again, an agreement that's been in place as technology moves so fast, it's been in place for five years, it's time to look at it again."

Feulner said that NAFTA has outdated provisions that must be updated, such as the prohibition on US energy exports to Mexico, which was created to protect US energy companies from the power of Mexico's then-state energy monopoly PEMEX.

"That's all now been broken up now. PEMEX no longer is the national monopoly and now we are stopping New Mexico from exporting natural gas into Mexico which doesn't make any sense," he said.

"There are parts of NAFTA that have to be looked at again, re-evaluated, negotiated. In the same kind of thing in terms of the KORUS-FTA." (Yonhap)