Rome, November 28 - NASA's Curiosity rover may have found a precursor to life on Mars, the director of the agency's Jet Propulsion Laboratory said Wednesday. "Perhaps Curiosity has found simple organic molecules," Charles Elachi said at the fringes of a Rome conference. "It's preliminary data that must be checked (on) organic, not biological, molecules". Broadly defined, organic molecules are characterized by containing carbon, which is present in all known life forms, but not necessarily evidence of life. Biological molecules, on the other hand, are produced only by living organisms. "Curiosity is not equipped to find traces of biological molecules," Elachi said, stressing that some media reports in recent weeks had gotten "carried away". Last week Curiosity Project scientist John Grotzinger told American public radio NPR that it was about to announce new findings. "This data is gonna be one for the history books. It's looking really good," he said. A number of news sources went on to say that NASA was set to reveal what could be "the most significant scientific discovery in modern times". While not traces of life itself, the discovery, if confirmed, would nonetheless keep the possibility open.