ABC News' Joohee Cho and Luis Martinez report:

SEOUL, South Korea - American and South Korean experts are cautious about a deal in which North Korea agreed to suspend much of its nuclear program and allow international inspectors monitor its plants in exchange for a massive shipment of U.S. food.

The experts were also trying to gauge whether the decision by North Korea was made by its young new leader Kim Jong Un or a committee of top officials.

"We've been down this road before," said said Lee Jung-Hoon, professor of International Relations at Yonsei University. "They will get food now, but there could be many excuses on what they not consider a productive dialogue and before actually letting those inspectors to set foot in Pyongyang."

The regime's decision is "reversible" because North Korea could "flip a switch and go in a different direction," noted a U.S. official who spoke to ABC News on the condition of anonymity.

North Korea has previously made deals with Washington concerning its nuclear program only to discard them later.

The elements in the deal are also not viewed as  a significant leap towards North Korea's nuclear disarmament, but are seen as "positive" and "modest steps" that could "unlock the door to the resumption eventually of six-party talks," a senior U.S. administration official told ABC News. The official added that he did not want to "oversell" Wednesday's announcement.

The announcement says that Pyongyang  will suspend uranium enrichment and impose a moratorium on nuclear and long-range missile tests, "with a view to maintaining positive atmosphere."

Pyongyang in Wednesday's statement said that it will allow the International Atomic Energy Administration to monitor the moratorium on uranium enrichment activity at Yongbyon "while productive dialogues continue."

That phrase, experts in Seoul say, is the usual North Korean tactic to leave room to back off.

Few details were released on the deal because both sides have much to work out and some will take time to go into effect, but it is designed to serve as a "good gauge" in demonstrating how serious North Korea is about resuming the Six Party Talks.

Experts are also using the agreement to gauge Kim Jong Un's role.

Kim Jong-Un has  "made it loud and clear that nuclear weapons are a legacy of his late-father," Lee said.  "For whatever reason, I think they are simply desperate in terms of food shortage at the time being."

A positive note is that North Korea's leadership is on track "picking up where the previous one left off."  The North Korean regime had been negotiating a similar deal late last year, but talks ended when Kim Jong Il died. 

Pyongyang's negotiator Kim Gye Gwan in Beijing last week was "very much informed, involved, engaged and, you know, calling the shots, though Kim, I'm sure, had some tactical running room" said a U.S. official. He could not determine whether the instructions were from a collective leadership or Kim Jong Un acting alone, but North Korea watchers in Seoul believe it was Kim.

"Decisions like this would come from its supreme leader, and for him, this is a win-win situation," said Yang Moo-Jin, professor at University of North Korean Studies.

Kim Jong-Un, believed to be in his late twenties, needs to prove to his regime and the people that he is capable of stabilizing foreign relations and rebuilding a stronger economy.  "He got the food aid, but he got it rightfully without losing face."

"It is also important that this step was taken as part of our new relationship with the Kim Jong Un regime. Western receptiveness on this issue, Kim Jong Un's first foreign policy step with the U.S., will do much to validate him within North Korea," said Donald Gregg, former U.S. ambassador to South Korea and ABC News consultant.

 The U.S. pledged 240,000 metric tons of nutritional assistance consisting of corn-soy blend, vegetable oil and possibly a modest amount of ready-to-use therapeutic foods. It is specifically intended for the populations suffering from chronic malnutrition - young children under the age of 6, pregnant women, and the elderly - "people whom the regime either cannot or has chosen not to feed," said the U.S. official.

North Korea had previously insisted that it receive large quantities of rice and grain which led the U.S. to conclude that it was probably intended for elites or the military. A UNICEF assessment in January concluded that 80 percent of the children in North Korea are malnourished.