U.S. President Donald Trump will press South Korean President Moon Jae-in to improve trade imbalances with the United States during meetings at the White House on Thursday and Friday, a White House official said.

In an interview with Reuters in April, Trump called the five-year-old KORUS trade pact "horrible" and "unacceptable" and said he would either renegotiate or terminate it.

Briefing reporters ahead of the visit, an official said Trump would raise concerns about barriers to U.S. auto sales in South Korea and "the enormous amount of steel that sometimes ends up being surplus Chinese steel that comes to the United States via South Korea."

"I think they'll have a friendly and frank discussion about the trade relationship," the official said.

KORUS was initially negotiated by the President George W. Bush administration in 2007, but was scrapped and renegotiated under President Barack Obama three years later.

The U.S. goods trade deficit with South Korea has more than doubled since KORUS took effect in 2012, from $13.2 billion in 2011 to $27.7 billion in 2016. It was forecast to boost U.S. exports by $10 billion a year, but they were $3 billion lower in 2016 than in 2011.