On Monday, North Korean leader Kim Jong-un delivered his 2018 New Year's Day address, as he has done every year since 2013.
South Korea's unification ministry said Tuesday it is "carefully" considering the timing of proposing talks with North Korea as the North's leader expressed his willingness to send a delegation to the PyeongChang Winter Olympics.
"The improvement of relations between North and South Korea can not go separately with resolving North Korea's nuclear program, so the foreign ministry should coordinate closely with allies and the worldwide community regarding this", Moon said in opening remarks at a cabinet meeting.
Kim's offer of talks and sporting co-operation with South Korea follows a year dominated by fiery rhetoric and escalating tensions over Pyongyang's nuclear weapons program.
The New Year's address is an annual event in North Korea and is watched closely for indications of the direction and priorities Kim may adopt in the year ahead.
Kim said during his address that his aim is to "lower the military tensions on the Korean Peninsula to create a peaceful environment".
Asked to comment on Kim's speech, U.S. President Donald Trump said: "We'll see, we'll see", as he walked into a New Year's Eve celebration at his Mar-a-Lago resort in Florida. Referring to the Olympics, he said later: "We're willing to take necessary steps including sending our delegation, and for this, the authorities from the North and South could urgently meet".
Last week, the UN Security Council unanimously adopted new sanctions on North Korea in response to Pyongyang's November 29 ballistic missile test, seeking to further strangle its energy supplies and tighten restrictions on smuggling and the use of North Korean workers overseas.
In his address, he also called for warming relations with South Korea. How things turn out, he said, rests on whether China puts more pressure North Korea.
He also proclaimed that his country achieved the historic feat of "completing" its nuclear forces in 2017.
North Korea hasn't immediately reacted. He said North Korea's nuclear deterrent was "irreversible" and that it would prevent Trump from starting a war.
An official from South Korea's Foreign Ministry said the 5,100-ton KOTI and its crew members were being held at Pyeongtaek-Dangjin port on the country's west coast amid an inspection over supposed "North Korea-related" activity.