North Korean leader Kim Jong-un has said he is committed to denuclearisation, but warned he will change course if the US continues its sanctions.
He made the remarks during his closely-watched annual New Year address.
Last year’s speech set the country on an unprecedented path of international diplomacy with South Korea and the US.
Mr Kim met US President Donald Trump to discuss denuclearisation in June 2018 but with few results so far.
Last year’s rapprochement came after a turbulent 2017 marked by North Korea testing missiles that could reach the US mainland and an escalation in rhetoric between Pyongyang and Washington with both sides trading insults and threats of nuclear destruction.
In the speech broadcast on state television early on Tuesday, Mr Kim said “if the US does not keep its promise made in front of the whole world… and insists on sanctions and pressures on our republic, we may be left with no choice but to consider a new way to safeguard our sovereignty and interests”.
He said he was ready to meet Mr Trump again at any time.
North Korea is subject to various sets of United Nations Security Council sanctions related to its banned nuclear and ballistic missile weapons programmes.
It was in last year’s New Year speech that Mr Kim announced North Korea would take part in the Winter Olympics hosted by the South, which led to a thaw in relations.
After a flurry of diplomatic activity, in April Kim Jong-un met South Korean President Moon Jae-in for a summit at the inter-Korean border.
They met another two times after that but the most historic summit of 2018 was the North Korean leader’s meeting with US President Donald Trump in Singapore in June.
In what was the first time a North Korean leader met a sitting US president, the two signed a vaguely phrased agreement to improve ties and work towards denuclearisation.
Since the Trump-Kim summit though, less progress has been made than at least optimists had been hoping for.
The North has dismantled some testing facilities but there are allegations it is continuing its weapons programme.
President Trump has said he expects a second summit to take place as early as February but there has been no confirmation yet.
There are also plans for Kim Jong-un to travel to the South’s capital Seoul for another inter-Korean summit but again, those plans have not been confirmed yet.