SCHLADMING, Austria (AFP) - US ski star Lindsey Vonn suffered a heavy crash during the opening race of the world championships here on Tuesday, but it was still unclear whether she suffered any serious injuries.

The 28-year-old two-time world champion and Olympic gold-medallist landed on the side of her ski after a jump during the opening super-G race here, and flipped over before crashing into a safety gate.

Emergency services were quickly on site, and Vonn was evacuated by helicopter to a nearby hospital.

Austrian television reported possible leg injuries.

The four-time World Cup winner was looking to recapture her super-G world title from 2009 and had been leading before her crash.