"As we look around the world at the end of 2013, we see examples of situations where that readiness of the international community to act in time is already being sorely tested," Navi Pillay, high commissioner for human rights, said during a news conference in Geneva, Switzerland.
"In addition to Syria, where the scale and viciousness of the abuses being perpetuated by elements on both sides almost defies belief, the situation in the Central African Republic is deteriorating rapidly, and the alarm bells are ringing loud and clear," she said.
She also pointed to the "serious politically driven instability" in Bangladesh in the run-up to the nation's elections and the "heavy handed attempts" in Egypt to tamp down peaceful protests.
Reprisals against organizations and individuals working for human rights and journalists working on rights issues in several countries also were "extremely worrying," Pillay said.
She also noted migrants still were treated as second-class citizens in many countries and that xenophobia and racism were being exploited in Europe and other industrialized areas.
"Amidst all this, there is nevertheless progress, sometimes taking place slowly and steadily out of the limelight, sometimes the subject of major policy shifts -- including a number of reforms announced over the past two weeks by the government of China," Pillay said.
Noting it was the 20th anniversary of the creation of the Office of the High Commissioner for Human Rights, Pillay said the U.N. human rights system was stronger now than when the office was first created.
Still, she said, "The U.N. human rights institutions, however well they function, are not enough by themselves" and called on other U.N. entities to back "the common cause of improving human rights for everyone everywhere, in accordance with the U.N. Charter."