(Reuters) - Six spectators were injured when lightning struck a tree during the third round at the Tour Championship in Atlanta on Saturday, the PGA Tour said in a statement.
"At 4.45 p.m., there were two lightning strikes at East Lake Golf Club; a tree near the range/15 green/16 tee was hit, and debris from that strike injured four people," the Tour said.
"(Emergency personnel) tended to those fans and two others immediately and transported them from the property via ambulance for further medical attention.
"Our latest report is that their injuries do not appear to be life-threatening."
The strike occurred 28 minutes after the third round had been halted when thunderstorms popped up over the course, said Tour rules official Mark Russell on the NBC broadcast.
"We knew we were going to have possibly some pop-up thunderstorms today," Russell said.
"When one did form right over the top of us we suspended play immediately."
Play was suspended for the day, and will resume at 8 a.m. (1200 GMT) local time on Sunday.
NBC screened footage showing the lightning bolt that apparently caused the injuries.
Professional golf tournaments became far more vigilant about stopping play amid the threat of lightning after two spectators were killed at separate major championships in the United States in 1991.
One man was killed and five others injured while sheltering under a tree at the 1991 U.S. Open at Hazeltine in Minnesota.
Two months later, another spectator died when struck while walking to his vehicle at the PGA Championship at Crooked Stick in Indiana.
However, while players and caddies are loaded into vehicles and taken back to the clubhouse in such situations, fans are left to seek their own shelter, and may lack the time to leave the course safely or choose not to do so.
Saturday's stoppage came after the leaders in the 30-man field had completed only five holes in the season-ending event.
Justin Thomas led fellow American Brooks Koepka and Northern Irishman Rory McIlroy by one stroke, while American Xander Schauffele was two behind.
The winner on Sunday will collect a record first prize of $15 million.
(Reporting by Andrew Both in Cary, North Carolina,; Editing by Toby Davis and Ed Osmond)