The U.S. envoy to the United Nations-hosted Conference on Disarmament says that Syria's presidency of the Geneva-based body is a "travesty."

Referring to killings and chemical weapons attacks allegedly committed against civilians by the Syrian government, Robert Wood said Tuesday "this is no normal presidency, and thus the U.S. will not treat it as such."

Syria took up the rotating presidency Monday. It will chair the body for a four-week period.

Wood said the "United States will not be silent" and called on other countries to "speak out" and send a "very similar and clear message about their abhorrence."

Wood walked out as Syria's envoy made opening remarks, but later returned.

The 65-nation conference is the world's most important disarmament negotiating forum, though it has achieved little in recent years.