The United Nations’ anti-racism conference will open on May 20 at Geneva, its European headquarters. Concerns rise that it might spark high tension and fall into clashes once again.

The Geneva conference is designed to review progress in fighting racism since the UN first held such conference eight years ago in Durban, South Africa.

That 2001 meeting, which ended four days before 9/11, was dominated by quarrels over the Middle East and the legacy of slavery. The United States and Israel walked out midway.

Many Muslim nations want curbs to free speech to prevent insults to Islam and they say they have been proliferated since the Sept.11, 2001 attacks on the United States. Riots erupted across the Muslim world after a Danish newspaper published cartoons of the Prophet Muhammad in 2005.

Many of the 2001 issues such as criticism of Israel, now are re-emerging. The United States and the European Union had not decided Friday whether to attend the meeting or boycott it over Islamic nations' demand to condemn Israel and call for a ban on defaming religion.

Israel and Canada have said they won't attend the meeting over concerns about a possible repeat of verbal attacks on the Jewish state.