Donald Trump vows to impose 'largest ever set of sanctions on North Korea' as Ivanka arrives in the South for Winter Olympics

Donald Trump has unveiled his largest package of sanctions yet against North Korea over the repressive state's nuclear and missile programme.

The news came as the US president's daughter Ivanka Trump arrived in South Korea, first attending a presidential dinner in Seoul before setting off to go to the Winter Olympics in Pyeongchang.

"Today I am announcing that we are launching the largest-ever set of new sanctions on the North Korean regime," Mr Trump said on Friday in a scheduled speech to the Conservative Political Action Conference near Washington, according to excerpts released by the White House.

The sanctions expand on an existing sanctions programme that has been building up since 2008 and will focus on 56 ships and firms, although it is not clear which ones or where.

In the opening of the speech Mr Trump joked about how he "tries like hell to hide his bald patch".

"The Treasury Department will soon be taking new action to further cut off sources of revenue and fuel that the regime uses to fund its nuclear program and sustain its military by targeting 56 vessels, shipping companies, and trade businesses that are assisting North Korea in evading sanctions," the US president said.

Tougher sanctions could jeopardise recent small steps forward in relations taken between the two Koreas, which are currently trying to lay down conditions for a summit between North Korean leader Kim Jong Un and South Korean President Moon Jae-in.

Vice President Mike Pence had hinted at the sanctions plan two weeks ago on a stop in Tokyo before his visit to South Korea for the Pyeongchang Winter Olympics.

North Korean leader Kim Jong Un has said he wants to boost the "warm climate of reconciliation and dialogue" with South Korea.

A high-level delegation including his sister attended the Winter Olympics as part of what Western diplomats have seen as a charm offensive, although no meetings are said to have taken place with US officials.

Last year, North Korea conducted dozens of missile launches and its sixth and largest nuclear test in defiance of United Nations sanctions. However, it has now been more than two months since its last missile test in late November.

The new US sanctions are being announced while Mr Trump's daughter, Ivanka, is in South Korea.

She has already attended a dinner with Mr Moon in Seoul and will go to the closing ceremony of the Games in Pyeongchang.

Her visit coincides with that of a sanctioned North Korean official, Kim Yong Chol, blamed for the deadly 2010 sinking of a South Korean navy ship that killed 46 sailors. His delegation is also meeting with Mr Moon.

The Blue House has said there are no official opportunities for US and North Korean officials to meet.