The US and other nations are boytcotting a meeting on the subject of international justice at the UN, which it says is being used by Serbia to divert attention from its role in the Balkan wars.
Organised by former Serbian Foreign Minister Vuk Jeremic, who is serving as president of the 193-nation assembly, the two-day meeting is considered as inflammatory and intended merely to complain about the treatment of Serbs in war crimes tribunals.
The meeting is due to end on Thursday.
"[The US and boycotting nations] feared it would be used as a venue to attack the work of the International Criminal Court for the former Yugoslavia, and it was," said Al Jazeera's diplomatic editor James Bays, reporting from the UN's headquarters in New York.
Jordan and Canada joined the US in boycotting the debate.
Some UN diplomats have privately accused Jeremic of using the General Assembly to promote his own career and his home country.
Jeremic told Reuters in an interview that he considered the event a success, but added it was "regrettable" some important countries like the US did not participate.
Envoys say that if Jeremic does not get Serbia's presidency, he is likely to try to become the next UN secretary-general, a position that is expected to be filled by an Eastern European.
Richard Dicker, director of Human Rights Watch's international justice programme, told Al Jazeera that "what was driving this debate was not a desire for objective, constructive look at stregths and weaknesses, but more an opportunity to drive a hatchet into the Yugoslav war crimes tribunal."
The European Union's 27 member nations are attending the event but sending junior diplomats.