Seoul, South Korea ? North Korea will sink deeper into diplomatic isolation and economic deterioration unless it abandons its nuclear weapons program, a South Korean official said Friday after an international group suspended future oil deliveries to the North.

South Korea, Japan, the European Union and the United States agreed Thursday to halt the fuel shipments to punish the communist country for its uranium enrichment program.

“I hope North Korea will understand well where we want to go on this issue. The ball is in the court of North Korea,” a senior South Korean government official said, speaking on condition of anonymity. “We want to carry on putting more pressure on North Korea so they understand the seriousness of all countries involved.”

There was no response Friday from North Korea, which has said it is willing to resolve U.S. security concerns in exchange for a nonaggression pact. The United States has said talks are out of the question as long as North Korea has a nuclear program.

The United States and its allies hope North Korea, which desperately needs the fuel, will buckle under the pressure and dismantle its nuclear weapons program.

The suspension of oil deliveries “will have a huge impact on North Korea,” said Choi Su-young of the Institute for National Unification, a state research center. “Many more factories there might be forced to grind to a halt.”

The decision to suspend oil shipments was made by a U.S.-led consortium that is building two nuclear reactors for civilian use in North Korea. Under a 1994 deal with Washington, North Korea was entitled to receive 550,000 tons of oil until the reactors were up and running.

In exchange for the energy aid, North Korea suspended a plutonium-based nuclear program that the United States feared was for military use. The North’s newly revealed nuclear program violates the 1994 deal and other anti-nuclear accords.

An oil tanker already on its way to North Korea will deliver its cargo. The suspension that was ordered by the consortium, the Korean Peninsula Energy Development Organization, or KEDO, starts in December.

Some estimates say KEDO fuel accounts for 10 percent of the oil needs of North Korea, which imports all of the oil it consumes. The North’s power grid is operating at 10 percent to 30 percent capacity, and most cities are virtually devoid of electricity at night.

While the oil suspension will deal a severe blow to the North Korean economy, the U.S.-led strategy carries risks. It will impose further hardship on the North Korean population, which is already dependent on outside food aid.

Also, rather than relent, North Korea could respond with a strategy of brinkmanship by threatening to revive its plutonium-based nuclear program, which experts believe could yield nuclear bombs relatively quickly. That program was the focus of a crisis in 1994 that nearly led to war, but ended in the accord that North Korea has since violated.

North Korea acknowledged its uranium bomb program on Oct. 4.