A key Donald Trump ally, who oversees his foreign policy, displayed deeply negative views of the U.S. free trade agreement with South Korea, saying the deal ended up increasing Korean exports to the U.S.

The remark by Sen. Jeff Sessions (R-AL) reinforces concern that Trump, if elected to the White House, could seek to overhaul the pact, which has been in effect since 2012 and is considered a symbol of the economic alliance between the two countries.

In an interview with Politico published Tuesday, Sessions said that even though he has supported many trade agreements so far, he has now come to believe Trump was right on the point that the agreements "have not been effective."

"I supported the Korean Trade Agreement in 2011. They promised -- when it was signed, President Obama said it would increase our exports to Korea by $10 billion a year," Sessions said.

"Since last year, 2015, there was no increase, like instead of billions of dollars there was like a $100 million increase in our exports to Korea, whereas their imports to us went up $12 billion, and our trade deficit increased 240 percent," he said.

Sessions also made clear his opposition to the Trans Pacific Partnership free trade deal.

It wasn't the first time Sessions has criticized the FTA with Korea.

During a Senate plenary meeting in late April, the senator also said that he supported the Korea FTA, but the deal "came nowhere close to being beneficial to the United States," adding that it only increased the U.S. trade deficit with Korea.

Walid Phares, a top foreign policy adviser to Trump, said in an interview with Yonhap News Agency and Yonhap News Television earlier this month that Trump wants to "go back to ground zero" and is ready to renegotiate the pact, even though he said renegotiation does not mean canceling everything.

South 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 South Korea has made more investments in the U.S. than the U.S. did in South Korea. (Yonhap)