United States peacekeepers have been granted immunity from prosecution by the International Criminal Court (ICC) despite strong objections from other countries, including Switzerland.
The Swiss ambassador to the United Nations, Jenö Staehelin, had earlier condemned the move, saying it "clearly undermined" the authority of the court.
On Thursday the United Nations Security Council approved a one-year extension to UN resolution 1422, which was adopted in July 2002.
The resolution authorises a year-long exemption from arrest or trial for peacekeepers from the United States and other countries that have not ratified the treaty establishing the court.
"Switzerland disagrees with the principle and the terms of resolution 1422," Staehelin told the UN Security Council on Thursday.
"Switzerland deplores the adoption, and even more, the prospect of renewing [the] resolution," he added.
Staehelin said it would be "very worrying to see the Security Council adopt a resolution which limits the scope of a treaty".
Switzerland was one of five countries which called for Thursday's debate and expressed grave concerns about Washington's stance.
Staehelin said granting immunity to peacekeepers in trouble spots would send out a message that the ICC was itself an "obstacle to peace".
The Swiss position was backed by UN Secretary-General Kofi Annan who said there was a danger of requests for exemption becoming an annual event.
Annan said a further one-year extension could "undermine not only the authority of the ICC, but also the authority and legitimacy of UN peacekeeping operations".
The ICC was established to try individuals for genocide, war crimes and systematic human rights abuses committed after July 1, 2002.
However, it will only step in when states are unwilling or unable to dispense justice.
Based in The Hague in the Netherlands, the court is due to start work next month.
swissinfo, Tania Peitzker
UN resolution 1422 came into force in July last year and exempts those countries that did not sign the founding treaty of the ICC.
The court is due to start processing cases next month.
The ICC was established to try individuals for war crimes committed after July 1, 2002.