SEOUL, South Korea — South Korean officials on Monday indicated that President Trump and North Korea’s leader, Kim Jong-un, could agree on a joint political statement declaring an end to the 1950-53 Korean War when they meet in Hanoi, Vietnam, this week.

“The possibility is open,” said Kim Eui-kyeom, a spokesman for South Korea’s president, Moon Jae-in, referring to the results expected from the Trump-Kim summit meeting scheduled for Wednesday and Thursday. “We still don’t know exactly what format the end-of-war declaration will take, but there is an ample possibility of North Korea and the United States agreeing to such a declaration.”

Mr. Moon has strongly advocated an end-of-war declaration to build trust between North Korea and the United States and to prod the North to move toward giving up its nuclear weapons. The North and the United States have remained technically at war since the Korean War was halted in a truce in 1953, and Washington still keeps 28,500 troops in South Korea to prevent it from rekindling.

Until now, South Korean officials, who are closely monitoring pre-summit meeting negotiations between North Korea and the United States, had sounded skeptical that Mr. Trump and Mr. Kim would agree to an end-of-war declaration during their Hanoi meeting. The remarks by the South Korean spokesman indicated such a declaration was now being seriously discussed as Mr. Trump seeks to encourage Mr. Kim to take steps toward denuclearization.

“The core economic sanctions, the sanctions that prevent countries from conducting trade, creating wealth for North Korea, those sanctions are definitely going to remain in place,” Mr. Pompeo told CNN. “We’ve said consistently full, verified denuclearization — that’s the standard for relieving those sanctions.”

Instead, American negotiators have been studying noneconomic incentives for the North, such as an end-of-war declaration or the exchange of liaison offices between Pyongyang and Washington, according to South Korean officials familiar with Washington’s talks with North Korean officials.

But it remained unclear whether an end-of-war declaration would persuade the North to commit to the kind of serious steps toward denuclearization that Washington demands, according to South Korean analysts and officials, who say the North will likely calibrate its commitment to denuclearization on whether Mr. Trump grants sanctions relief, the North’s top priority.

American and South Korean analysts have expressed fear that declaring an end to the war would give Mr. Kim reason to demand that the United States withdraw its 28,500 troops from the South while the North remains a nuclear-armed state.

But South Korean officials said the declaration would be merely a “political statement” that would “give the North Koreans some comfort.” North Korea has long argued that it was forced to develop a nuclear deterrent because of American “hostility,” and that it would keep that deterrent until it felt safe from American aggression.

South Korea had earlier hoped that an end-of-war declaration would be made in the presence of Mr. Moon and even China’s president, Xi Jinping. China fought for North Korea during the war, while American troops fought alongside the South Koreans.

But on Monday, Mr. Kim, the presidential spokesman, said that unlike a peace treaty that should be negotiated among the two Koreas, the United States and China, a bilateral end-of-war declaration between the United States and North Korea could be enough. The United States and South Korea now have formal diplomatic ties with China, making such a declaration irrelevant to Beijing. South and North Korea have signed military and other agreements in recent months that Mr. Kim said were tantamount to a nonaggression treaty.

“The North and the United States are the only ones remaining, and if the two declare an end to the war, it will mean that all the four countries that fought war on the Korean Peninsula have declared an end to war,” he said. “Our government welcomes an end-of-war declaration no matter what format it might take, as long as it helps encourage and advance denuclearization.”

But the spokesman said an end-of-war declaration is “different from the peace treaty.” The peace treaty could be signed only “at the end stage of denuclearization,” he said.

Mr. Moon on Monday urged his people to prepare for a possible fundamental shift in relations on the Korean Peninsula after the Hanoi summit meeting.

“If the upcoming summit produces results, now is the real beginning,” he was quoted as saying during a meeting with his senior presidential staff. “Standing at the center of history, not the periphery, we will take the lead in preparing for a new Korean Peninsula regime — one that is moving from war and confrontation toward peace and harmony, and from factionalism and ideology toward economic prosperity.”