SEOUL (BLOOMBERG, AFP, REUTERS) - North and South Korea staged on Wednesday (Dec 26) a symbolic ground-breaking ceremony for reconnecting roads and railways across the divided peninsula despite stalled denuclearisation talks.

A nine-car special train carrying about 100 South Koreans, including officials and five people born in the North, was seen leaving Seoul railway station early in the morning for a two-hour journey to the North's border city of Kaesong.

They were joined by a 100-strong North Korean delegation, as well as officials from the United Nations, China, Russia and Mongolia, according to South Korea's Unification Ministry.

The ceremony started at 10am local time (9am Singapore time), South Korean media including Yonhap News Agency reported.

"The result of the North and South Korean railway and road project depends on our nation's mental strength and will. If we are swayed by others' views, we cannot achieve the unification that our nation wants," Kim Yun Hyok, North Korea's vice railway minister, said at the ceremony, according to the YTN TV network.

"Railways will now also play a role of reducing the gap between the hearts of South and North Korea," South Korean Transport Minister Kim Hyun-mee said.

The Chinese ambassador to South Korea, Qiu Guohong, told South Korea's Minister Kim during the event Wednesday that he believed the railway project would help denuclearisation.

The United States and the UN Security Council gave their support for the ceremony, South Korean officials said, but construction cannot begin while sanctions block the shipment of energy and metal products, as well as other supplies.

"There's a lot of things to do before we actually start construction," Minister Kim said, adding the two sides would conduct additional joint surveys and design work for one or two years.

There was a feeling of nervous excitement on the South Korean train as it left the capital Seoul.

"I'm just deeply moved," said Shin Jang-chul, who drove the last freight train between the Koreas a decade ago. "It's been 10 years and I've been wondering if I would ever be able to come back after I retire," he added.

South Korean President Moon Jae-in and the North's leader Kim Jong Un agreed to hold the ceremony by the end of this year when they met at their third summit in Pyongyang in September.

While South Korea said the Security Council granted an exemption to United Nations sanctions on Tuesday to allow the ceremony to proceed, additional relief would be needed for the start of actual work on reconnecting and modernising road and rail links between the two Koreas - which remain technically at war after their 1950-53 conflict ended without a peace treaty.

The event is a mere "expression of a commitment" to the projects, a South Korean Unification Ministry spokesman said, adding that construction would depend on "progress on the North's denuclearisation and circumstances concerning sanctions". The two sides wrapped up their joint railway and road inspections for the projects this month.

South Korea has set aside about US$620,000 (S$850,000) for the endeavour.

The ceremony comes as the United States ramps up efforts to convince Pyongyang to give up its nuclear weapons.

Following a rapid rapprochement earlier this year that culminated in a historic summit between US President Donald Trump and Mr Kim, progress has stalled, with both sides accusing the other of dragging their feet and acting in bad faith.

Critics say North Korea has made no concrete commitments and is unlikely to surrender its atomic arsenal, while Washington's policy of maintaining pressure through isolation and sanctions has left Pyongyang seething.

Second summit

Mr Trump said on Monday that he was "looking forward" to his second summit with Mr Kim, which Washington says may take place early next year.

He tweeted the statement after he was briefed by Mr Stephen Biegun, the US special representative on North Korea, who wrapped up a three-day trip to Seoul last Saturday.

Mr Biegun said last week that the US would be more lenient in enforcing its blanket ban on US citizens' travel to the totalitarian state when dealing with aid workers, a goodwill gesture as Mr Trump seeks a fresh summit.

The Trump administration has generally refused to let US aid groups operate in North Korea, seeking to both maximise pressure on Pyongyang and ensure the safety of Americans.

Mr Biegun also said in Seoul last week that Washington was willing to discuss trust-building initiatives with Pyongyang.

Pyongyang hasn't responded to Washington's latest overtures.