The UN secretary general has urged the Security Council not to renew an exemption from prosecution for US troops on UN peacekeeping duties.
The US fears its troops could be prosecuted for political reasons
Kofi Annan said the exemption, passed for two years running and due to expire on 30 June, would discredit the UN's claim to represent the rule of law.
The US fears its troops could be prosecuted on war crimes charges for political reasons.
Mr Annan said abuses in Iraq made the issue particularly relevant.
INTERNATIONAL CRIMINAL COURT
Treaty creating ICC signed by 139 states, ratified by 94
Nations not to have ratified include US, Russia, Israel and Iran
ICC began functioning in 2003
"For the past two years, I have spoken quite strongly against the exemption and I think it would be unfortunate for one to press for such an exemption, given the prisoner abuse in Iraq," he told reporters.
"Blanket exemption is wrong. It is of dubious judicial value and I don't think it should be encouraged by the Council."
The US is among 139 nations to sign the Rome Treaty setting up the International Criminal Court in July 2002.
The international court will prosecute war crimes like genocide if national courts are unable, or unwilling, to do so.
However, like Russia, Israel and others, the US has not ratified the treaty out of fears that troops may be prosecuted for war crimes by foreign courts.
UN diplomats say America may find it difficult to get the necessary nine votes to pass the exemption resolution in the Security Council, the BBC's Susannah Price reports.
The Americans drew up the resolution in May and then postponed the vote saying they wanted to get the resolution on Iraq's handover dealt with first.
They say they are determined to ensure the perpetrators of abuses in Iraq are prosecuted despite the exemption.
However, human rights groups say the US should demonstrate that it will abide by international standards.
UK Foreign Office Minister Bill Rammell said his country, a Security Council member, is prepared to consider extending the US exemption because a defeat could harm peacekeeping operations around the world.
"We need American support... when the need for those operations has never been greater," he said.