The US is strongly critical of the move against General Franks
A lawsuit accusing the commander of US troops in Iraq of war crimes has been filed in a Belgian court - but has come under immediate attack from the Belgian authorities.
Foreign Minister Louis Michel described the move as an "abuse of the law", adding that Brussels had "no pretensions to judge the United States".
Earlier US Joint Chiefs Chairman Richard Myers said the situation was being viewed "very seriously" by the US Government, and that it may stop US officials taking part in meetings at Nato HQ in Brussels.
The plaintiffs, mostly Iraqis, filed the suit against General Tommy Franks under Belgium's "universal competence" law, which allows charges to be brought regardless of where crimes are alleged to have been committed.
The case concerns the alleged victims of US cluster bombs in Iraq, as well as incidents where US troops are accused of firing on ambulances and civilians, lawyer Jan Fermon said.
It is thought unlikely that the case will succeed.
Washington has already warned that Belgium's status as an international hub could be affected unless the "universal competence" law is restricted.
The action against General Franks is likely to be a test of recent revisions to the law following high profile cases brought against the Israeli Prime Minister Ariel Sharon and the former US President George Bush senior.
Judges can now pass war crimes cases onto other countries or reject them if they are not brought by Belgian citizens.
The plaintiffs in the latest case comprise 17 Iraqis and two Jordanians - the widow and father of Tareq Ayub, a Jordanian correspondent for Arabic broadcaster al-Jazeera, killed on 8 April when a US tank shell hit a Baghdad hotel.
Mr Fermon told reporters: "General Franks is responsible as commander in chief for the way some of his men acted on the ground. For instance, the use of cluster bombs on civilian areas is a war crime."
The suit also names Marine Lieutenant-Colonel Brian MacCoy, who
is accused of categorising the ambulances as "legitimate targets"
because he suspected them of harbouring gunmen, AFP said.
But Professor Jan Wouters, director of the Institute for International Law at the University of Leuven, said the suit "could be just a spectacular way of catching attention in the media".