Stryper guitarist Oz Fox suffered a seizure onstage over the weekend.

The band said he underwent medical tests after the emergency and was warned not to drive or fly for 90 days, meaning the group will complete its upcoming Australian tour as a trio.

The first word of Oz's medical emergency came from Jason Green, one of Fox’s colleagues in the rotating-lineup band Sin City Sinners. “At the end of tonight's Sin City Sinners show, Oz fell down due to a medical condition,” Green said (via Bravewords). “Scotty [Griffin, Sin City Sinners' singer] went with him to the hospital, and Oz's wife is there with him now. I'm told Oz is responsive and has good vitals.”

Green’s comments were followed by an official statement from Stryper. “Our dear friend and lead guitarist Oz Fox fell ill Saturday night while performing in Las Vegas with a side project that he sometimes plays in when not touring with Stryper," they wrote. "Oz suffered a seizure causing a fall onstage. After performing an MRI, doctors discovered an area of concern near his brain, which they are now running a biopsy on. The doctors have instructed him not to drive or fly for 90 days. No additional information is available at this time. We appreciate your thoughts and prayers and we will communicate additional information as it becomes available.”

The band said discussions were underway regarding its upcoming tour, with the Australian dates starting on Aug. 17 to be performed by the trio of Michael Sweet, Robert Sweet and Perry Richardson. U.S. dates were expected to remain as scheduled. “For our fans in Japan, please await an announcement from the concert promoter there as to the plans for the Japan tour,” they added.

Stryper released their 10th album, God Damn Evil, earlier this year.