Stricter international sanctions will only lead North Korea to speed up its nuclear programme, according to Pyongyang.
The news comes as US and Chinese leaders agreed to "maximise the pressure" on the regime of Kim Jong Un.
"The increased moves of the US and its vassal forces to impose sanctions and pressure on the DPRK will only increase our pace towards the ultimate completion of the state nuclear force," a statement on North Korean state media said.
The UN Security Council imposed fresh sanctions on North Korea a week ago over its nuclear and ballistic missile programmes, seeking to curb Pyongyang's sources of income, in part by limiting oil exports to the country.
The sanctions came on top of measures issued last month that were expected to cut roughly 1 billion dollars from the regime's 3 billion dollars in annual export revenue.
The United States is "disseminating the fraudulent claim that the sanctions and pressure are geared to the so-called peaceful solution. The US is strangling and suffocating a country and breaking its will," the statement said.
US President Donald Trump had discussed North Korea's "continued defiance of the international community" with President Xi Jinping, the White House said on Monday.
The two leaders "committed to maximising pressure on North Korea through vigorous enforcement of United Nations Security Council resolutions," a statement said.
China has traditionally been North Korea's closest international ally, although the North's repeated missile tests have hardened Beijing's line on the Kim regime.
North Korea is expected to be a main talking point at the UN General Assembly in New York this week.
