South Korea has slammed US President Donald Trump's suggestion that Seoul should pay for the Terminal High-Altitude Area Defense (Thaad) missile system that is now being deployed in the country. Trump had earlier questioned why the US was paying for the system that he valued at $1bn (£775m).

"I informed South Korea it would be appropriate if they paid. It's a billion dollar system," Trump said in an interview with Reuters on Thursday (27 April). "It's phenomenal, shoots missiles right out of the sky."

"There is no change in South Korea and the United States' position that our government provides the land and supporting facilities and the US bears the cost of Thaad system's deployment, operation and maintenance," South Korea's defence ministry responded.

Despite strong opposition from China, the US military started deploying the Thaad in early March in a bid to help South Korea intercept Pyongyang's ballistic missiles and defend itself against a potential missile attack from the isolated country.

The deployment has also been a major topic of discussion in South Korea's ongoing presidential race. Front runner Moon Jae-in's top foreign policy adviser said Trump's suggestion that Seoul pay for Thaad would be an "impossible option".

"Even if we purchase THAAD, its main operation would be in the hands of the United States," said Kim Ki-jung, foreign policy adviser to Moon and professor at Seoul's Yonsei University. "So purchasing it would be an impossible option. That was our topic when we were considering the options."

Trump's remarks came after the US started bringing in launchers, radar and other key elements of the advanced anti-missile defence system to the site in Seongju, south of the country, on 26 April. The surprise move to accelerate the deployment came amid tensions in the peninsula following North Korea's acts of belligerence, showing off its fire power.

Moon had called the move very inappropriate and regrettable and said it stripped the next Seoul government of its right to decide on its own about Thaad.

A US military vehicle, which is a part of Terminal High Altitude Area Defense, or Thaad system arrives in Seongju, South Korea on 26 April 2017 Kim Jun-beom/Yonhap via Reuters

'Horrible' Korus deal

In the interview with Reuters, Trump also called the Korea-US free trade agreement "horrible" as he vowed to either terminate or negotiate it after revamping the North American Free Trade Agreement (Nafta) with Mexico and Canada.

"It is unacceptable, it is a horrible deal made by Hillary," Trump said, as he placed the blame on his former presidential rival Hillary Clinton. "It's a horrible deal, and we are going to renegotiate that deal or terminate it."

The agreement known as the US-Korea (Korus) trade deal was approved by Congress in 2011 after Clinton, the then secretary of state, promoted the final version of the pact.

The president said he would very soon announce when he was planning to start with the renegotiation process.

Donald Trump
President Donald Trump said he would very soon announce when he was planning to start with renegotiating the US-South Korea free trade deal after threatening to scrap it Kevin Lamarque/Reuters

Trump's comments seem to have taken South Korean businesses by surprise. An official from South Korea's automakers' association told Reuters that the group was now worried about the "uncertainty" of the free-trade deal.

"Talk and actual policy are different. They [the Trump administration] have not requested anything from us so we'll have to wait and see," a top South Korean finance ministry official, speaking anonymously, said.