Social media posts have recirculated an old video of US President Donald Trump and falsely presented it as depicting him calling South Korean leader Lee Jae Myung a "bad negotiator" after their countries agreed a trade deal.

The deal, announced by Donald Trump, came after South Korean officials met with the US president on Wednesday, sparing one of the world’s biggest exporters from a 25 per cent tariff just a day before sweeping American levies on other countries were set to take effect.

The agreement comes after other American allies, like Japan, clinched their own deals, partly to moderate President Trump’s tariff threats.