Propaganda posters, presumed to be from North Korea, that call US President Donald Trump a 'mad dog' have turned up across central Seoul.

It is thought the flyers could have been flown across the highly fortified border to South Korea by balloon.

According to posts on social media, some of the propaganda pictures were found near the presidential Blue House.

'Death to old lunatic Trump!' reads one poster, which features a North Korean soldier crushing what looks to be the president's head. Near the guard's head is the line: 'Complete obliteration.'

The left poster shows a North Korean soldier stamping on the head Donald Trump alongside the words 'death to old lunatic Trump'. The right shows North Korean missiles aimed at the US Capitol building

Another flyer shows Trump with the body of a dog being decapitated by an axe.

Blood is shown splattered on the axe in the poster, which states: 'Let's behead mad dog Trump for the future of a peaceful and warless world and mankind!'

Both of the posters were in colour.

Military images and anti-US threats are common in North Korean propaganda as Pyongyang demands the United States cease what it says is its preparations for invasion.

But the new series of flyers posted recently on Twitter and other social media target Trump specifically.

Trump last month, in a speech to the United Nations, threatened to 'totally destroy' North Korea if needed to defend itself and allies and called the North's leader Kim Jong Un a 'rocket man' on a suicide mission.

Another flyer shows Trump with the body of a dog being decapitated by an axe

'I am pretty sure it came from North Korea by balloon, since the prevailing winds during October have been from north to south and we've been getting reports of others finding them throughout Seoul,' said Chad O'Carroll, managing director of NK News, a Seoul-based news subscription service, who found the leaflets while jogging in central Seoul.

In an apparent jab at Trump's U.N. speech, one of the propaganda posters featured Trump standing behind a podium with a rocket in his mouth painted with the words 'totally destroy North Korea'.

Again, Trump is depicted as a dog with a human face and labelled as 'mad dog Trump'.

Trump is depicted as a dog again with a human face and labelled as 'mad dog Trump'. Men in suits with surprised looks on their faces are shown in the poster saying 'He's gone completely insane' and 'If we let him be, there will be war'

Men in suits with surprised looks on their faces are shown in the poster saying 'He's gone completely insane' and 'If we let him be, there will be war'.

Reclusive North Korea, which has carried out a series of nuclear and missile tests in defiance of U.N. sanctions, and the rich, democratic South are technically still at war because their 1950-53 conflict ended in a truce, not a peace treaty.

The North regularly threatens to destroy the South and its main ally, the United States.