He said the United States believed climate change was a "well-known" controversy and that there were "other venues" to discuss it.
"Our desire is that this does not distract from this process," Lagon said.

He said other countries including Australia and Iran had also "raised concerns" about references to climate change.

"The US is not the only country asking questions about climate references," he said.

"This is not the dominant controversy" at the conference, Lagon said. "But there are different views."

US President George W. Bush rejected the Kyoto protocol on global warming after he took office in 2001, saying it would cost US industry too much.

The protocol calls for emission cuts of six key gasses. It comes into force in February after the agreement of Russia.

The US stance has infuriated Europe and other allies in the industrialized world which have signed up for Kyoto.

Some 4,500 experts and officials from around 150 countries are meeting in Kobe and are expected to make a list of targets to be met by 2015 on ways to reduce the risks of disasters.

A top issue at the conference is how to set up an early warning system for tsunamis, amid outrage that Indian Ocean nations had no way of knowing about the giant waves that battered their coasts on December 26 killing more than 168,000 people.

Lagon said the United States was fully committed to helping build an early warning system.

But experts here have called for measures to reduce the risks of all disasters and cited global warming as a concern.

UN relief chief Jan Egeland in his opening address Tuesday to the five-day conference said that in addition to natural disasters, "We now face threats of our own collective making: global warming, environmental degradation and uncontrolled urbanization."