The U.N. Security Council passed new sanctions on North Korea on Sept. 11 in light of North Korea's most recent nuclear tests. (Reuters)

North Korea on Tuesday condemned the U.N. Security Council’s decision to impose tougher sanctions and doubled down on its warning that the United States would “suffer the greatest pain” it has ever experienced for leading the effort to ratchet up economic pressures on the reclusive nation.

The United Nations on Monday unanimously agreed on its toughest sanctions against North Korea, setting limits on its oil imports and banning its textile exports. The United States and its allies had pushed for new sanctions to increase pressure on North Korea to agree to negotiations.

“My delegation condemns in the strongest terms and categorically rejects the latest illegal and unlawful U.N. Security Council resolution,” North Korean Ambassador Han Tae Song told the U.N.-sponsored Conference on Disarmament in Geneva, according to Reuters.

Han said Washington “fabricated the most vicious sanction resolution,” news agencies reported.

A photo distributed by the North Korean government shows leader Kim Jong Un, second from right, at an undisclosed location in North Korea. (AP)

He said North Korea is “ready to use a form of ultimate means” but did not elaborate, Reuters reported. North Korea had warned ahead of the U.N. vote that the United States would pay a “due price” if it pursues stronger sanctions.

In remarks at the start of his White House meeting with Malaysian Prime Minister Najib Razak, President Trump called the new sanctions “just another very small step.”

But, he warned without elaborating, “those sanctions are nothing compared to what ultimately will have to happen.”

The Security Council resolution was a watered-down version of what the United States and its allies had initially sought: a full embargo on North Korea’s crucial crude oil supply, which would have crippled the country.

But China and Russia, both veto-wielding members of the Security Council, were wary of measures such as cutting off oil that would seriously destabilize North Korea. The United States agreed to tone down some of its demands to secure the votes of China and Russia.

About 90 percent of North Korean trade goes through China, and China is North Korea’s main source of fuel.

Treasury Secretary Steven Mnuchin said at a conference hosted by CNBC on Tuesday that he would pursue sanctions against China if it does not adhere to the Security Council resolution.

“If China doesn’t follow these sanctions, we will put additional sanctions on them and prevent them from accessing the U.S. and international dollar system, and that’s quite meaningful,” he said, according to news agencies.

The latest round of sanctions could have a significant effect on the North Korean economy, potentially cutting up to $1.3 billion in annual revenue.

Before Monday’s vote, the Security Council already had imposed sanctions on North Korea, including on its exports of coal, iron ore and seafood.

But the measures did little to change North Korea’s behavior. The country conducted its sixth and most powerful nuclear test on Sept. 3, detonating a device that it claimed was a hydrogen bomb designed to be carried by a long-range missile capable of reaching the U.S. mainland.

The international community widely condemned the test.

The latest resolution caps North Korea’s imports of refined and crude oil at 8.5 million barrels a year, which represents a 30 percent cut, said Nikki Haley, the U.S. ambassador to the United Nations. Textile exports, banned under the resolution, represent more than a quarter of North Korea’s export income. More than 90 percent of North Korea’s reported exports are now fully banned under sanctions, Haley said.

South Korea praised the latest U.N. resolution, calling on North Korea to stop “trying to test the will of the international community.” It added that the “only way to break away from diplomatic isolation and economic oppression is to return to a table of dialogues for complete, irreversible, verifiable nuclear dismantlement.”