North Korea announced Wednesday that it would halt major aspects of its nuclear weapons program and allow the return of international inspectors, a breakthrough in negotiations with the United States, which offered the country’s authoritarian government food aid and a pledge of no “hostile intent.”

Under the agreement — the first sign of progress after years of stalled U.S. efforts to persuade North Korea to abandon its nuclear arsenal — the government in Pyongyang said it would suspend its nuclear weapons tests, enrichment of uranium and long-range-missile launches, according to the State Department.

The agreement doesn’t resolve the threat still posed by North Korea’s existing nuclear arsenal. The country has struck similar deals before, only to renege on them later, and the announcement of the deal by North Korea’s state-run media Wednesday also appeared to add a caveat, noting that the government would abide by the pact “while productive dialogues continue.”

Still, the agreement marks the first indication since North Korea’s Kim Jong Eun came to power late last year that the government is at least interested in engaging with the West and lowering tensions on the Korean Peninsula.

“This is what we had been trying to do for the last year,” said Stephen Bosworth, who until recently was President Obama’s special envoy on North Korea. “It’s a sign that the North Koreans want to have continuity. . . . First they need the food aid, and I think they probably want a relatively quiet political environment to carry on the transition.”

The Obama administration described the agreement as “important, if limited.”

Willingness to reengage

Many U.S. officials had feared that Kim, the son of the late Kim Jong Il, might seek to establish himself through military provocations such as attacks on South Korea. The move to engage with the United States could be an attempt by the young leader — thought to be in his late 20s — to demonstrate authority, bringing 240,000 metric tons of desperately needed food to the famine-stricken country at a politically crucial time.

But the younger Kim’s role in the deal is unknown, even to U.S. officials who hammered out the agreement with North Korea last week in Beijing.

“We were sitting across from essentially the same North Korean negotiators who have been at this in some cases for, well, for decades. . . . The way that they presented the issues was quite familiar to us,” said a senior administration official, who was not authorized to speak on the record. The North Koreans’ willingness to reengage, however, shows the Stalinist government is interested in “picking up where the previous one left off — and that’s great,” the official said.

In the years since its first nuclear test in 2006, some experts have estimated that North Korea has amassed enough plutonium to produce up to 12 nuclear warheads. But recent discoveries have complicated that picture.

In 2010, its leaders revealed to a visiting American nuclear scientist a secretly built uranium-enrichment facility at its Yongbyon complex — a discovery that sparked alarm in Washington, as well as in Seoul and Tokyo. Uranium can be used for peaceful energy production, but when highly enriched, it can also be used as fuel for nuclear arms.

As part of the pact announced Wednesday, North Korea agreed to allow inspectors from the International Atomic Energy Agency to return to Yongbyon, but experts noted that even if inspectors are allowed to conduct thorough tests there, no one knows how many other such facilities might exist.

“The thing with plutonium reactors was that the signature was visible from the sky. You had cooling towers and other components,” said Victor Cha, a former White House director of Asian affairs who is now a senior adviser at the Center for Strategic and International Studies. “But with uranium, you can store a lot of centri­fuges in a warehouse anywhere.”

U.S. officials were on the cusp of reaching an almost-identical deal before Kim Jong Il’s death in December. Many observers were surprised at the speed at which the new deal came together, noting that North Korea is still observing a 100-day mourning period.

U.S. officials said they had been in touch with the North Koreans through channels at the United Nations and had sent signals for weeks that they were open to returning to the negotiating table.

Then, a few weeks ago, U.S. officials began picking up signals that the North Koreans were equally game.

“One moment it was something that seemed absolutely impossible and out of the question, and then literally a day or two later, a switch had been flicked, and they were ready to go,” the senior administration official said.

Ploy or progress?

Neither side got everything it wanted, said several officials who were briefed on the negotiations.

U.S. officials had pushed in recent months for North Korea to commit to improving its tense relations with South Korea — a key American ally — and refraining from further provocations. The deal announced Wednesday did not include language on either.

Yun Duk-min of South Korea’s Institute of Foreign Affairs and National Security said that while the deal on food aid is significant, it may not help improve inter-Korean relations since it did not involve the South.

For its part, North Korea had asked for more food aid but received only an initial commitment for 240,000 metric tons. U.S. officials have expressed concern that the food aid could be diverted to the governing elite, as has happened previously with U.S. humanitarian assistance.

U.S. leaders have insisted that the food aid is a humanitarian issue and should be treated entirely separately from nuclear disarmament — a point the Obama administration reemphasized Wednesday. But the North Koreans have made clear that they see the two as inexorably linked.

Republicans in Congress pounced on that point Wednesday, accusing the administration of blurring the line. “It appears that the administration is actively reneging on its assurances that it would not provide any financial incentives or food aid to North Korea in exchange for dubious commitments of cooperation toward denuclearization,” Sen. Jon Kyl (R-Ariz.) said in a statement.

U.S. and North Korean representatives will meet in coming days to work out the logistics of delivering and monitoring the food, according to the State Department. In the meantime, U.S. officials described the deal as a possible step toward resuming six-party talks among the two Koreas, the United States, China, Japan and Russia. Those talks, which could yield further pledges from Pyongyang, stalled in 2008, with the North Koreans eventually walking out to protest international criticism of a banned rocket launch.

Meanwhile, North Korea’s top nuclear negotiator, Ri Yong Ho, is expected to attend a security forum at Syracuse University in upstate New York next week, the Associated Press reported Thursday.

Pyongyang’s latest assurances “could indeed be an initial step on a path towards serious negotiations,” said Richard C. Bush III, a North Korea expert at the Brookings Institution. “Or they could simply be a ploy to get nutritional assistance and meddle in South Korean politics. North Korea’s record suggests the latter, but we shall see.”

Correspondent Chico Harlan in Tokyo and Special Correspondent Yoonjung Seo in Seoul contributed to this report.