The United Nations has said that United States air strikes on Venezuela and the seizure of the country’s leader over the weekend clearly undermined a fundamental principle of international law.

“States must not threaten or use force against the territorial integrity or political independence of any state,” Ms. Ravina Shamdasani, spokeswoman for the UN Office of the High Commissioner for Human Rights, told reporters in Geneva on Tuesday.

“And this is what we are seeing,” she said, calling on the international community to “come together with one voice … to make clear that this is an action that is in contravention of the international law that was set up by member states”.

US commandos, backed by warplanes, naval forces, and air strikes, forcibly seized Venezuelan President Nicolas Maduro and his wife, Mrs. Cilia Flores, in the early hours of Saturday.

Mr. Maduro appeared in court in New York on Monday, where he denied drug trafficking and other charges brought by Washington. He insisted that he had been kidnapped and maintained that he remained Venezuela’s president.

Mr. Maduro became president in 2013 after succeeding his populist mentor, Mr. Hugo Chavez.

The United States and the European Union have accused Mr. Maduro of remaining in power by rigging elections — most recently in 2024 — imprisoning opponents, and presiding over widespread corruption.

Ms. Shamdasani said the UN human rights office had spent years reporting on the “continued deterioration” of the situation in Venezuela.

However, she dismissed US justifications for its actions, stating that accountability for human rights violations “cannot be achieved by unilateral military intervention in violation of international law”.

“Using human rights arguments as a justification for this kind of military intervention is unacceptable,” she said, adding that she feared the US intervention “will only make the situation worse”.

Ms. Shamdasani noted that a state of emergency declared by Venezuelan authorities on Saturday permits property seizures, restricts freedom of movement, and suspends the right to protest, among other measures.

“Far from being a victory for human rights, this military intervention … damages the architecture of international security, making every country less safe,” she said.

The UN human rights office has been monitoring the situation from Panama since its international staff were expelled from Venezuela in early 2024.

Meanwhile, the UN humanitarian agency, OCHA, said nearly eight million people in Venezuela — about a quarter of the population — required humanitarian assistance even before the US operation.

The UN refugee agency, UNHCR, said it had yet to see signs of mass displacement since Saturday.

UNHCR spokeswoman Ms. Eujin Byun said the agency was closely monitoring developments and was ready to “support emergency relief efforts and to protect displaced people in need as required”.