Pope Francis today called for dialogue over Korea, a legally binding ban on nuclear weapons and the retention of the 'status quo' in Jerusalem in his annual speech to diplomats known as his 'state of the world' address.

The Pope also addressed climate change, calling for countries to remain committed to the 2015 Paris accord on reducing carbon emissions. Donald Trump has announced that the United States will withdraw from the agreement.

'It is of paramount importance to support every effort at dialogue on the Korean peninsula, in order to find new ways of overcoming the current disputes, increasing mutual trust and ensuring a peaceful future for the Korean people and the entire world,' Francis said.

Francis addressed diplomats a day before North Korea and South Korea are due to hold talks expected to address North Korea's participation in the Pyeongchang Winter Olympics.

Earlier this month, after North Korean leader Kim Jong Un asserted that he had a nuclear button at the ready, Trump tweeted that the US button at his disposal was bigger and more powerful.

'Nuclear weapons must be banned,' Francis said, quoting a document issued by Pope John XXIII at the height of the Cold War and adding that there is 'no denying that the conflagration could be started by some chance and unforeseen circumstance'.

The Pope noted that the Holy See was among 122 states that last year agreed to a United Nations treaty to ban nuclear weapons. The US, Britain, France and others boycotted the talks that led to the treaty, instead pledging commitment to a decades-old Non-Proliferation Treaty.

The Pope's comments on Jerusalem came after Trump unilaterally announced in December that the US was controversially recognising the city as the capital of Israel. At the time, Pope Francis said 'I cannot keep silent my deep concern' over the issue.

Additional reporting by Reuters.