The United States and its partners on Tuesday dealt the death blow to a project to build two light-water atomic reactors for North Korea to entice it into dismantling its nuclear weapons program, officials said.

The decade-old light-water reactor project had been mothballed for the last two years, kept barely alive in case North Korea showed signs of resuming International Atomic Energy Agency inspections and liquidating its ambitious self-proclaimed nuclear weapons program.

The New York-based Korean Peninsula Energy Development Organization, also known as KEDO, did not issue any formal statement at the end of a two-day session of executive board meetings Tuesday.

But the U.S. delegate, Ambassador Joseph DiTrani, said after the meeting that the board members — the United States, South Korea, Japan and European Union — had agreed on the "termination" of the light-water reactor project, KEDO spokesman Brian Kremer confirmed.

The decision comes at a particularly delicate moment in the fitful series of six-nation talks aimed at disarming North Korea. The fifth round of talks among the two Koreas, the United States, Russian, China and Japan ended Nov. 11 without signs of major progress.

Charles Kartman, the American who was executive director of KEDO from 2001 until this August, said North Korea must have anticipated KEDO's demise.

"There's no surprise here for North Korea. They've been setting up their obstacles" for weeks and in September had revived their demand for the reactors, Kartman said.

At the end of the fourth round of six-way talks in September, North Korea pledged in principle to disarm but maintained that it would need light-water reactors to provide electricity beforehand. Fulfilling that demand would postpone effective disarmament for several years.

At a summit of Asian and Pacific leaders last week, President Bush said no reactors would be considered before the North gives up its nuclear weapons program.

Meanwhile, North Korea says it is escalating its nuclear weapons development program, the problem that spiked both Korean crises in recent years — in 1993-1994 and again in 2002 through today.

A shutdown of the Yongbyon research reactor in 1989 and reactor slowdowns in 1990-1991 are believed to have yielded enough plutonium to build two or three bombs, a situation that the Clinton administration considered so threatening that it brought the United States and North Korea close to war in 1994.

A bilateral nuclear inspection accord and deal to build two monitored light-water reactors cooled tensions and led to the KEDO project.

Last May, North Korea's Foreign Ministry said the country had the ability to harvest still more weapons-grade plutonium and "bolster its nuclear arsenal."

"You have to assume the North Koreans have weaponized the plutonium," Kartman said.

Under the agreement that formed the KEDO project, North Korea was to abandon nuclear weapons development and allow access by International Atomic Energy Agency inspectors, in exchange for 500,000 tons of heavy fuel oil annually from the United States to meet its energy shortage until it got the two light-water atomic power plants, built and paid for primarily by South Korea and Japan, with some EU funding.

The program was frozen in 2002 after the United States claimed North Korea had embarked on a second, secret weapons-development program. Evidence to back the claim has never been publicly disclosed.