Space exploration should focus on better understanding Mars' environment before searching for life on the red planet, according to scientists at an international forum here.

U.S., Soviet and European scientists gathered at Florida State University disagreed Saturday about whether there is, or was, life on Mars and how to seek it.But they concurred that unmanned missions should stress fundamental research as the foundation for the search for life.

"We need more understanding of the environment before we can progress with the search for life," said Christopher McKay of the U.S. National Aeronautics and Space Administration.

Most of the data that scientists have come from the twin Viking spacecraft NASA dispatched to Mars in 1975. Two orbiters photographed the barren surface while a pair of life-seeking landers touched down.

Despite their sophistication, the Vikings provided only a glimpse of what Mars is like, according to Harold Klein, a California researcher involved with the project.

"It is fair to say there was no convincing evidence obtained to suggest the presence of extant life at either landing site," Klein told the forum.

The exobiologists - specialists in the search for life on other worlds - painted a picture of Mars as a planet with a lush genesis much like Earth's, in which living organisms might have begun to develop.

Both planets were chilled by an Ice Age, but unlike Earth, Mars never warmed up again. Whatever water that was not frozen evaporated as Mars' atmosphere disappeared.

"The central most important fact is it once had liquid water, and that's the quintessential ingredient for life," McKay said.