SINGAPORE -- Investors looking for business opportunities in North Korea will have to wait to pop the champagne.

Tuesday's historic summit between the U.S. and North Korea has laid the groundwork for further interaction between the two old foes. But without any details on North Korea's denuclearization and sanctions relief, it is hard for investors to act.

"North Korea obviously has a lot of untapped economic potential," said Shawn Ho, an associate research fellow at the S. Rajaratnam School of International Studies, Nanyang Technological University, in Singapore.

Recently the country has decided to shift its focus from nuclear development to economic development, but "it's just a question of how to do it, given the sanctions still in place," Ho said. "To these questions, I didn't get a really clear answer" from the summit.

Ho said that North Korea can survive without immediate sanctions relief, adding that it is a very resilient economy. "I think they will get by," he said. "They will be able to cope."

There are also signs of entrepreneurial activity at the grassroots level. But spontaneous initiatives have never been allowed to grow on any significant scale. Experts say this is because the country's leaders fear these risk-takers could destabilize the regime.

Donald Trump and Kim Jong Un were not expected to announce any big breakthroughs at their summit.

"We don't think [a blue-sky scenario] is reachable in the short term," said Goohoon Kwon, co-head of Korea research at Goldman Sachs, on Tuesday, speaking before full details of the agreement came out. He was referring to a big breakthrough toward denuclearization and diplomatic normalization between Washington and Pyongyang.

For the market, what really matters is implementation and execution, not promises, Kwon added.

The U.S. did try to push North Korea into bold action, without success.

"We've got to make bold decisions," U.S. Secretary of State Mike Pompeo said on June 7, urging Pyongyang to act decisively, as he raised the prospects of diplomatic normalization, economic aid and sanctions relief.

Holding the summit in Singapore was part of the strategy.

On the eve of the summit, Pompeo highlighted that Singapore is home to over 4,000 American companies. Despite Chinese being the majority ethnic group, the city-state maintains an equal distance from the West and China and thrives as a global commercial hub.

Trump also showed Kim a video, produced by Americans, depicting what a prosperous North Korea could look like, with investment pouring in from around the world.

"Will this leader choose to advance his country and be part of the new world and be the hero of his people?" the video asked its North Korean audience. "Will he shake the hand of peace and enjoy prosperity like he has never seen?"

During his three-day stay in the city-state, Kim took a two-hour nighttime tour of Singapore's waterfront sightseeing spots, including the Marina Bay Sands casino resort.

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Unlike his grandfather, North Korea's founding leader Kim Il Sung, and his father and predecessor, Kim Jong Il, the young Kim has lived in the West, having been educated in Switzerland.

Yet the summit has shown that North Korea's leader, thought to be in his mid-30s, is disinclined to follow the American script. The fact that he traveled to Singapore aboard Air China jetliner indicates he does not wish to depend on the U.S. or South Korea for its future, said Lee Chanwoo, an associate professor at Teikyo University Junior College, in Tokyo.

"While the U.S. is offering promises for the future, China takes care of the everyday needs of North Korea," Lee said. "They don't want to trade a bird in the hand for two in the bush."

Over the next few months, Lee added, each side needs to take steps to prove that it can offer concrete benefits to the other and build trust.